Using iOS 14’s Menu as a Picker in SwiftUI

Up until iOS 13, the options available for inline pickers felt limited. We could show the wheel inline, but that doesn’t look great in table views, lists, and forms. The other option was to use the navigation stack. But if we didn’t want to use the navigation stack, handling pickers could be painful.

Apart from those two options supported directly by iOS, many apps tried to solve this problem by showing the wheel in the keyboard area. Some apps even decided to use an action sheet, which in my opinion is a bad design choice.

Will iOS 14 help us solve this problem? If we look at the documentation for PickerStyle, there is no update for iOS 14. Where else can we look?

I was watching the Design with iOS Menus and Pickers session for WWDC 20 and there was a mention of using menus for selection.

#ios #swift #xcode #swiftui

What is GEEK

Buddha Community

Using iOS 14’s Menu as a Picker in SwiftUI
Mike  Kozey

Mike Kozey

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Test_cov_console: Flutter Console Coverage Test

Flutter Console Coverage Test

This small dart tools is used to generate Flutter Coverage Test report to console

How to install

Add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):

dev_dependencies:
  test_cov_console: ^0.2.2

How to run

run the following command to make sure all flutter library is up-to-date

flutter pub get
Running "flutter pub get" in coverage...                            0.5s

run the following command to generate lcov.info on coverage directory

flutter test --coverage
00:02 +1: All tests passed!

run the tool to generate report from lcov.info

flutter pub run test_cov_console
---------------------------------------------|---------|---------|---------|-------------------|
File                                         |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
 print_cov_constants.dart                    |    0.00 |    0.00 |    0.00 |    no unit testing|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|

Optional parameter

If not given a FILE, "coverage/lcov.info" will be used.
-f, --file=<FILE>                      The target lcov.info file to be reported
-e, --exclude=<STRING1,STRING2,...>    A list of contains string for files without unit testing
                                       to be excluded from report
-l, --line                             It will print Lines & Uncovered Lines only
                                       Branch & Functions coverage percentage will not be printed
-i, --ignore                           It will not print any file without unit testing
-m, --multi                            Report from multiple lcov.info files
-c, --csv                              Output to CSV file
-o, --output=<CSV-FILE>                Full path of output CSV file
                                       If not given, "coverage/test_cov_console.csv" will be used
-t, --total                            Print only the total coverage
                                       Note: it will ignore all other option (if any), except -m
-p, --pass=<MINIMUM>                   Print only the whether total coverage is passed MINIMUM value or not
                                       If the value >= MINIMUM, it will print PASSED, otherwise FAILED
                                       Note: it will ignore all other option (if any), except -m
-h, --help                             Show this help

example run the tool with parameters

flutter pub run test_cov_console --file=coverage/lcov.info --exclude=_constants,_mock
---------------------------------------------|---------|---------|---------|-------------------|
File                                         |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|

report for multiple lcov.info files (-m, --multi)

It support to run for multiple lcov.info files with the followings directory structures:
1. No root module
<root>/<module_a>
<root>/<module_a>/coverage/lcov.info
<root>/<module_a>/lib/src
<root>/<module_b>
<root>/<module_b>/coverage/lcov.info
<root>/<module_b>/lib/src
...
2. With root module
<root>/coverage/lcov.info
<root>/lib/src
<root>/<module_a>
<root>/<module_a>/coverage/lcov.info
<root>/<module_a>/lib/src
<root>/<module_b>
<root>/<module_b>/coverage/lcov.info
<root>/<module_b>/lib/src
...
You must run test_cov_console on <root> dir, and the report would be grouped by module, here is
the sample output for directory structure 'with root module':
flutter pub run test_cov_console --file=coverage/lcov.info --exclude=_constants,_mock --multi
---------------------------------------------|---------|---------|---------|-------------------|
File                                         |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|
---------------------------------------------|---------|---------|---------|-------------------|
File - module_a -                            |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|
---------------------------------------------|---------|---------|---------|-------------------|
File - module_b -                            |% Branch | % Funcs | % Lines | Uncovered Line #s |
---------------------------------------------|---------|---------|---------|-------------------|
lib/src/                                     |         |         |         |                   |
 print_cov.dart                              |  100.00 |  100.00 |   88.37 |...,149,205,206,207|
lib/                                         |         |         |         |                   |
 test_cov_console.dart                       |    0.00 |    0.00 |    0.00 |    no unit testing|
---------------------------------------------|---------|---------|---------|-------------------|
 All files with unit testing                 |  100.00 |  100.00 |   88.37 |                   |
---------------------------------------------|---------|---------|---------|-------------------|

Output to CSV file (-c, --csv, -o, --output)

flutter pub run test_cov_console -c --output=coverage/test_coverage.csv

#### sample CSV output file:
File,% Branch,% Funcs,% Lines,Uncovered Line #s
lib/,,,,
test_cov_console.dart,0.00,0.00,0.00,no unit testing
lib/src/,,,,
parser.dart,100.00,100.00,97.22,"97"
parser_constants.dart,100.00,100.00,100.00,""
print_cov.dart,100.00,100.00,82.91,"29,49,51,52,171,174,177,180,183,184,185,186,187,188,279,324,325,387,388,389,390,391,392,393,394,395,398"
print_cov_constants.dart,0.00,0.00,0.00,no unit testing
All files with unit testing,100.00,100.00,86.07,""

Installing

Use this package as an executable

Install it

You can install the package from the command line:

dart pub global activate test_cov_console

Use it

The package has the following executables:

$ test_cov_console

Use this package as a library

Depend on it

Run this command:

With Dart:

 $ dart pub add test_cov_console

With Flutter:

 $ flutter pub add test_cov_console

This will add a line like this to your package's pubspec.yaml (and run an implicit dart pub get):

dependencies:
  test_cov_console: ^0.2.2

Alternatively, your editor might support dart pub get or flutter pub get. Check the docs for your editor to learn more.

Import it

Now in your Dart code, you can use:

import 'package:test_cov_console/test_cov_console.dart';

example/lib/main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
        // This makes the visual density adapt to the platform that you run
        // the app on. For desktop platforms, the controls will be smaller and
        // closer together (more dense) than on mobile platforms.
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

Author: DigitalKatalis
Source Code: https://github.com/DigitalKatalis/test_cov_console 
License: BSD-3-Clause license

#flutter #dart #test 

How To Use Datepicker In Angular for Beginners

Angular Datepicker is a built-in material component that allows us to enter the date through text input or by choosing the date from a calendar. Angular Material Datepicker allows users to enter the date through text input or by choosing the date from the calendar. The Material Datepicker comprises several components and directives that work together.

It is made up of various angular components and directives that work together. First, we need to install AngularWe are using Angular CLI to install the Angular.

1: Install the Angular CLI.

Type the following command.

npm install -g @angular/cli

Now, create the Angular project using the following command.

ng new datepicker

2: Install other libraries.

Go into the project and install the hammerjs using the following command.

npm install --save hammerjs

Hammer.js is the optional dependency and helps with touch support for a few components.

Now, install Angular Material and Angular Animations using the following command.

npm install --save @angular/material @angular/animations @angular/cdk

Now, include hammerjs inside the angular.json file. You can find this file at the root of the project.

3: Import a pre-built theme and Material icons.

Angular Material comes with some pre-built themes. These themes have set off the colors and basic styling.

The main available themes are indigo-pink, deeppurple-amber, purple-green, and pink-bluegrey.

To import the theme, you can add the following code to your global styles.css file. The file is inside the src folder.

@import '~@angular/material/prebuilt-themes/indigo-pink.css';

You can also access the Material Design icons and use named icons with a <mat-icon> component.

If we want to import them to your project, we can add this to the head section of your project’s root index.html file.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Datepicker</title>
  <base href="/">

  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="icon" type="image/x-icon" href="favicon.ico">
  <link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
</head>
<body>
  <app-root></app-root>
</body>
</html>

4: Create a Custom Material Module File.

Inside the src,>> app folder, create one file called material.module.ts and add the following code.

// material.module.ts

import { NgModule } from '@angular/core';
import { MatDatepickerModule } from '@angular/material';

@NgModule({
  imports: [
    MatDatepickerModule
  ],
  exports: [
    MatDatepickerModule
  ]
})

export class MaterialModule {}

We have imported MatDatepickerModule, MatNativeDateModule, and other components that we need in our Angular Datepicker Example App.

We can add additional components in the future if we need to.

This file is written on its own because it is easy to include all the Material components in this file, and then this file will be imported inside the app.module.ts.

// material.module.ts

import { NgModule } from '@angular/core';
import { MatDatepickerModule,
        MatNativeDateModule,
        MatFormFieldModule,
        MatInputModule } from '@angular/material';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

@NgModule({
  imports: [
    MatDatepickerModule,
    MatFormFieldModule,
    MatNativeDateModule,
    MatInputModule,
    BrowserAnimationsModule
  ],
  exports: [
    MatDatepickerModule,
    MatFormFieldModule,
    MatNativeDateModule,
    MatInputModule,
    BrowserAnimationsModule
  ],
  providers: [ MatDatepickerModule ],
})

export class MaterialModule {}

5: Import MaterialModule in an app.module.ts file.

Import MaterialModule inside the app.module.ts file.

// app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { MaterialModule } from './material.module';

import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    MaterialModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Also, finally, write the Datepicker HTML code inside the app.component.html file.

<!-- app.component.html -->

<mat-form-field>
  <input matInput [matDatepicker]="picker" placeholder="Choose a date">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

Save the file, go to a terminal or cmd, and start Angular Development Server.

ng serve --open

Angular Datepicker Example | How To Use Datepicker In Angular

Go to the browser, and see something like the below image.

Angular 6 Datepicker Example Tutorial

6: Connecting a datepicker to an input

A datepicker comprises text input and a calendar popup, connected via the matDatePicker property on the text input.

<input [matDatepicker]="myDatepicker">
<mat-datepicker #myDatepicker></mat-datepicker>

There is an optional datepicker toggle button available. The toggle button can be added to the example above:

<input [matDatepicker]="myDatepicker">
<mat-datepicker-toggle [for]="myDatepicker"></mat-datepicker-toggle>
<mat-datepicker #myDatepicker></mat-datepicker>

It works the same with an input that is part of a <mat-form-field> and a toggle button can easily be used as a prefix or suffix on the material input:

<mat-form-field>
  <input matInput [matDatepicker]="myDatepicker">
  <mat-datepicker-toggle matSuffix [for]="myDatepicker"></mat-datepicker-toggle>
  <mat-datepicker #myDatepicker></mat-datepicker>
</mat-form-field>

7: Setting the calendar starting view

The startView property of <mat-datepicker> could be used to set the look that will show up when the calendar first opens. It can be configured to month, year, or multi-year; by default, it will begin to month view.

A month, year, or range of years that a calendar opens to is determined by first checking if any date is currently selected, and if so, it will open to a month or year containing that date. Otherwise, it will open in a month or year, providing today’s date.

This behavior can be easily overridden using the startAt property of <mat-datepicker>. In this case, a calendar will open to the month or year containing the startAt date.

<mat-form-field>
  <input matInput [matDatepicker]="picker" placeholder="Choose a date">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker startView="year" [startAt]="startDate"></mat-datepicker>
</mat-form-field>

Angular Material Datepicker Example Tutorial

You can find the code on Github.

Angular Datepicker Validation

Three properties add the date validation to the datepicker input.

The first two are the min and max properties.

Also, to enforce validation on input, these properties will disable all the dates on the calendar popup before or after the respective values and prevent the user from advancing the calendar past the month or year (depending on current view) containing the min or max date.

See the following HTML markup.

<mat-form-field class="example-full-width">
  <input matInput [min]="minDate" [max]="maxDate" [matDatepicker]="picker" placeholder="Choose a date">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

 Also, see the typescript file related to the above markup.

import {Component} from '@angular/core';

/** @title Datepicker with min & max validation */
@Component({
  selector: 'datepicker-min-max-example',
  templateUrl: 'datepicker-min-max-example.html',
  styleUrls: ['datepicker-min-max-example.css'],
})
export class DatepickerMinMaxExample {
  minDate = new Date(2000, 0, 1);
  maxDate = new Date(2020, 0, 1);
}

The second way to add the date validation is by using the matDatepickerFilter property of the datepicker input.

This property accepts a function of <D> => boolean (where <D> is the date type used by the datepicker, see Choosing a date implementation).

A true result indicates that the date is valid, and a false result suggests that it is not.

Again this will also disable the dates on a calendar that are invalid.

However, a critical difference between using matDatepickerFilter vs. using min or max is that filtering out all dates before or after a certain point will not prevent a user from advancing a calendar past that point.

See the following code example. See first the HTML markup.

<mat-form-field class="example-full-width">
  <input matInput [matDatepickerFilter]="myFilter" [matDatepicker]="picker" placeholder="Choose a date">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

 Now, see the Typescript file related to the above markup.

import {Component} from '@angular/core';

/** @title Datepicker with filter validation */
@Component({
  selector: 'datepicker-filter-example',
  templateUrl: 'datepicker-filter-example.html',
  styleUrls: ['datepicker-filter-example.css'],
})
export class DatepickerFilterExample {
  myFilter = (d: Date): boolean => {
    const day = d.getDay();
    // Prevent Saturday and Sunday from being selected.
    return day !== 0 && day !== 6;
  }
}

In this example, the user can go back past 2005, but all of the dates before then will be unselectable. They will not be able to go further back in the calendar than 2000.

If they manually type in a date before the min, after the max, or filtered out, the input will have validation errors.

Each validation property has a different error that can be checked:

  1. For example, the value that violates a min property will have the matDatepickerMin error.
  2. The value that violates a max property will have the matDatepickerMax error.
  3. The value that violates a matDatepickerFilter property will have the matDatepickerFilter error.

Angular Input and change events

The input’s native (input) and (change) events will only trigger user interaction with the input element; they will not fire when the user selects the date from the calendar popup.

Therefore, a datepicker input also has support for (dateInput) and (dateChange) events — these triggers when a user interacts with either an input or the popup.

The (dateInput) event will fire whenever the value changes due to the user typing or selecting a date from the calendar. Likewise, the (dateChange) event will fire whenever the user finishes typing input (on <input> blur) or when a user chooses the date from a calendar.

See the following HTML Markup.

<mat-form-field>
  <input matInput [matDatepicker]="picker" placeholder="Input & change events"
         (dateInput)="addEvent('input', $event)" (dateChange)="addEvent('change', $event)">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

<div class="example-events">
  <div *ngFor="let e of events">{{e}}</div>
</div>

 Now, see the typescript file related to that markup.

import {Component} from '@angular/core';
import {MatDatepickerInputEvent} from '@angular/material/datepicker';

/** @title Datepicker input and change events */
@Component({
  selector: 'datepicker-events-example',
  templateUrl: 'datepicker-events-example.html',
  styleUrls: ['datepicker-events-example.css'],
})
export class DatepickerEventsExample {
  events: string[] = [];

  addEvent(type: string, event: MatDatepickerInputEvent) {
    this.events.push(`${type}: ${event.value}`);
  }
}

Disabling parts of the Angular Datepicker

As with any standard <input>, it is possible to disable the datepicker input by adding the disabled property.

By default, the <mat-datepicker> and <mat-datepicker-toggle> will inherit their disabled state from the <input>, but this can be overridden by setting a disabled property on the datepicker or toggle elements.

This is very useful if you want to disable the text input but allow selection via the calendar or vice-versa.

See the following HTML Markup.

<p>
  <mat-form-field>
    <input matInput [matDatepicker]="dp1" placeholder="Completely disabled" disabled>
    <mat-datepicker-toggle matSuffix [for]="dp1"></mat-datepicker-toggle>
    <mat-datepicker #dp1></mat-datepicker>
  </mat-form-field>
</p>

<p>
  <mat-form-field>
    <input matInput [matDatepicker]="dp2" placeholder="Popup disabled">
    <mat-datepicker-toggle matSuffix [for]="dp2" disabled></mat-datepicker-toggle>
    <mat-datepicker #dp2></mat-datepicker>
  </mat-form-field>
</p>

<p>
  <mat-form-field>
    <input matInput [matDatepicker]="dp3" placeholder="Input disabled" disabled>
    <mat-datepicker-toggle matSuffix [for]="dp3"></mat-datepicker-toggle>
    <mat-datepicker #dp3 disabled="false"></mat-datepicker>
  </mat-form-field>
</p>

 Now, see the typescript file.

import {Component} from '@angular/core';

/** @title Disabled datepicker */
@Component({
  selector: 'datepicker-disabled-example',
  templateUrl: 'datepicker-disabled-example.html',
  styleUrls: ['datepicker-disabled-example.css'],
})
export class DatepickerDisabledExample {}

That’s it for this tutorial.

Using iOS 14’s Menu as a Picker in SwiftUI

Up until iOS 13, the options available for inline pickers felt limited. We could show the wheel inline, but that doesn’t look great in table views, lists, and forms. The other option was to use the navigation stack. But if we didn’t want to use the navigation stack, handling pickers could be painful.

Apart from those two options supported directly by iOS, many apps tried to solve this problem by showing the wheel in the keyboard area. Some apps even decided to use an action sheet, which in my opinion is a bad design choice.

Will iOS 14 help us solve this problem? If we look at the documentation for PickerStyle, there is no update for iOS 14. Where else can we look?

I was watching the Design with iOS Menus and Pickers session for WWDC 20 and there was a mention of using menus for selection.

#ios #swift #xcode #swiftui

Angular Datepicker: How to use Datepicker in Angular 13

Angular Material is ground running with significant, modern UI components that work across the web, mobile, and desktop

Angular Material components will help us construct attractive UI and UX, consistent and functional web pages, and web applications while keeping to modern web design principles like browser portability and compatibility, device independence, and graceful degradation.

Angular Datepicker

Angular Datepicker is a built-in material component that allows us to enter the date through text input or by choosing the date from a calendar. Angular Material Datepicker allows users to enter the date through text input or by choosing the date from the calendar. The Material Datepicker comprises several components and directives that work together.

It is made up of various angular components and directives that work together. First, we need to install Angular. We are using Angular CLI to install the Angular.

Step 1: Install the Angular CLI.

Type the following command.

npm install -g @angular/cli

Now, create the Angular project using the following command.

 

ng new datepicker

Step 2: Install other libraries.

Go into the project and install the hammerjs using the following command.

npm install --save hammerjs

Hammer.js is the optional dependency and helps with touch support for a few components.

Now, install Angular Material and Angular Animations using the following command.

npm install --save @angular/material @angular/animations @angular/cdk

Now, include hammerjs inside the angular.json file. You can find this file at the root of the project.

Step 3: Import a pre-built theme and Material icons.

Angular Material comes with some pre-built themes. These themes have set off the colors and basic styling.

The main available themes are indigo-pinkdeeppurple-amberpurple-green, and pink-bluegrey.

To import the theme, you can add the following code to your global styles.css file. The file is inside the src folder.

@import '~@angular/material/prebuilt-themes/indigo-pink.css';

You can also access the Material Design icons and use named icons with a <mat-icon> component.

If we want to import them to your project, we can add this to the head section of your project’s root index.html file.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Datepicker</title>
  <base href="/">

  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="icon" type="image/x-icon" href="favicon.ico">
  <link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
</head>
<body>
  <app-root></app-root>
</body>
</html>

Step 4: Create a Custom Material Module File.

Inside the src,>> app folder, create one file called material.module.ts and add the following code.

// material.module.ts

import { NgModule } from '@angular/core';
import { MatDatepickerModule } from '@angular/material';

@NgModule({
  imports: [
    MatDatepickerModule
  ],
  exports: [
    MatDatepickerModule
  ]
})

export class MaterialModule {}

We have imported MatDatepickerModule, MatNativeDateModule, and other components that we need in our Angular Datepicker Example App.

We can add additional components in the future if we need to.

This file is written on its own because it is easy to include all the Material components in this file, and then this file will be imported inside the app.module.ts.

// material.module.ts

import { NgModule } from '@angular/core';
import { MatDatepickerModule,
        MatNativeDateModule,
        MatFormFieldModule,
        MatInputModule } from '@angular/material';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

@NgModule({
  imports: [
    MatDatepickerModule,
    MatFormFieldModule,
    MatNativeDateModule,
    MatInputModule,
    BrowserAnimationsModule
  ],
  exports: [
    MatDatepickerModule,
    MatFormFieldModule,
    MatNativeDateModule,
    MatInputModule,
    BrowserAnimationsModule
  ],
  providers: [ MatDatepickerModule ],
})

export class MaterialModule {}

Step 5: Import MaterialModule in an app.module.ts file.

Import MaterialModule inside the app.module.ts file.

// app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { MaterialModule } from './material.module';

import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    MaterialModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Also, finally, write the Datepicker HTML code inside the app.component.html file.

<!-- app.component.html -->

<mat-form-field>
  <input matInput [matDatepicker]="picker" placeholder="Choose a date">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

Save the file, go to a terminal or cmd, and start Angular Development Server.

ng serve --open

Angular Datepicker Example | How To Use Datepicker In Angular

Go to the browser, and see something like the below image.

Angular 6 Datepicker Example TutorialStep 6: Connecting a datepicker to an input

A datepicker comprises text input and a calendar popup, connected via the matDatePicker property on the text input.

<input [matDatepicker]="myDatepicker">
<mat-datepicker #myDatepicker></mat-datepicker>

There is an optional datepicker toggle button available. The toggle button can be added to the example above:

<input [matDatepicker]="myDatepicker">
<mat-datepicker-toggle [for]="myDatepicker"></mat-datepicker-toggle>
<mat-datepicker #myDatepicker></mat-datepicker>

It works the same with an input that is part of a <mat-form-field> and a toggle button can easily be used as a prefix or suffix on the material input:

<mat-form-field>
  <input matInput [matDatepicker]="myDatepicker">
  <mat-datepicker-toggle matSuffix [for]="myDatepicker"></mat-datepicker-toggle>
  <mat-datepicker #myDatepicker></mat-datepicker>
</mat-form-field>

Step 7: Setting the calendar starting view

The startView property of <mat-datepicker> could be used to set the look that will show up when the calendar first opens. It can be configured to monthyear, or multi-year; by default, it will begin to month view.

A month, year, or range of years that a calendar opens to is determined by first checking if any date is currently selected, and if so, it will open to a month or year containing that date. Otherwise, it will open in a month or year, providing today’s date.

This behavior can be easily overridden using the startAt property of <mat-datepicker>. In this case, a calendar will open to the month or year containing the startAt date.

<mat-form-field>
  <input matInput [matDatepicker]="picker" placeholder="Choose a date">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker startView="year" [startAt]="startDate"></mat-datepicker>
</mat-form-field>

Angular Material Datepicker Example Tutorial

You can find the code on Github.

GITHUB CODE

Angular Datepicker Validation

Three properties add the date validation to the datepicker input.

The first two are the min and max properties.

Also, to enforce validation on input, these properties will disable all the dates on the calendar popup before or after the respective values and prevent the user from advancing the calendar past the month or year (depending on current view) containing the min or max date.

See the following HTML markup.

<mat-form-field class="example-full-width">
  <input matInput [min]="minDate" [max]="maxDate" [matDatepicker]="picker" placeholder="Choose a date">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

 Also, see the typescript file related to the above markup.

import {Component} from '@angular/core';

/** @title Datepicker with min & max validation */
@Component({
  selector: 'datepicker-min-max-example',
  templateUrl: 'datepicker-min-max-example.html',
  styleUrls: ['datepicker-min-max-example.css'],
})
export class DatepickerMinMaxExample {
  minDate = new Date(2000, 0, 1);
  maxDate = new Date(2020, 0, 1);
}

The second way to add the date validation is by using the matDatepickerFilter property of the datepicker input.

This property accepts a function of <D> => boolean (where <D> is the date type used by the datepicker, see Choosing a date implementation).

A true result indicates that the date is valid, and a false result suggests that it is not.

Again this will also disable the dates on a calendar that are invalid.

However, a critical difference between using matDatepickerFilter vs. using min or max is that filtering out all dates before or after a certain point will not prevent a user from advancing a calendar past that point.

See the following code example. See first the HTML markup.

<mat-form-field class="example-full-width">
  <input matInput [matDatepickerFilter]="myFilter" [matDatepicker]="picker" placeholder="Choose a date">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

 Now, see the Typescript file related to the above markup.

import {Component} from '@angular/core';

/** @title Datepicker with filter validation */
@Component({
  selector: 'datepicker-filter-example',
  templateUrl: 'datepicker-filter-example.html',
  styleUrls: ['datepicker-filter-example.css'],
})
export class DatepickerFilterExample {
  myFilter = (d: Date): boolean => {
    const day = d.getDay();
    // Prevent Saturday and Sunday from being selected.
    return day !== 0 && day !== 6;
  }
}

In this example, the user can go back past 2005, but all of the dates before then will be unselectable. They will not be able to go further back in the calendar than 2000.

If they manually type in a date before the min, after the max, or filtered out, the input will have validation errors.

Each validation property has a different error that can be checked:

  1. For example, the value that violates a min property will have the matDatepickerMin error.
  2. The value that violates a max property will have the matDatepickerMax error.
  3. The value that violates a matDatepickerFilter property will have the matDatepickerFilter error.

Angular Input and change events

The input’s native (input) and (change) events will only trigger user interaction with the input element; they will not fire when the user selects the date from the calendar popup.

Therefore, a datepicker input also has support for (dateInput) and (dateChange) events — these triggers when a user interacts with either an input or the popup.

The (dateInput) event will fire whenever the value changes due to the user typing or selecting a date from the calendar. Likewise, the (dateChange) event will fire whenever the user finishes typing input (on <input> blur) or when a user chooses the date from a calendar.

See the following HTML Markup.

<mat-form-field>
  <input matInput [matDatepicker]="picker" placeholder="Input & change events"
         (dateInput)="addEvent('input', $event)" (dateChange)="addEvent('change', $event)">
  <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
  <mat-datepicker #picker></mat-datepicker>
</mat-form-field>

<div class="example-events">
  <div *ngFor="let e of events">{{e}}</div>
</div>

 Now, see the typescript file related to that markup.

import {Component} from '@angular/core';
import {MatDatepickerInputEvent} from '@angular/material/datepicker';

/** @title Datepicker input and change events */
@Component({
  selector: 'datepicker-events-example',
  templateUrl: 'datepicker-events-example.html',
  styleUrls: ['datepicker-events-example.css'],
})
export class DatepickerEventsExample {
  events: string[] = [];

  addEvent(type: string, event: MatDatepickerInputEvent) {
    this.events.push(`${type}: ${event.value}`);
  }
}

Disabling parts of the Angular Datepicker

As with any standard <input>, it is possible to disable the datepicker input by adding the disabled property.

By default, the <mat-datepicker> and <mat-datepicker-toggle> will inherit their disabled state from the <input>, but this can be overridden by setting a disabled property on the datepicker or toggle elements.

This is very useful if you want to disable the text input but allow selection via the calendar or vice-versa.

See the following HTML Markup.

<p>
  <mat-form-field>
    <input matInput [matDatepicker]="dp1" placeholder="Completely disabled" disabled>
    <mat-datepicker-toggle matSuffix [for]="dp1"></mat-datepicker-toggle>
    <mat-datepicker #dp1></mat-datepicker>
  </mat-form-field>
</p>

<p>
  <mat-form-field>
    <input matInput [matDatepicker]="dp2" placeholder="Popup disabled">
    <mat-datepicker-toggle matSuffix [for]="dp2" disabled></mat-datepicker-toggle>
    <mat-datepicker #dp2></mat-datepicker>
  </mat-form-field>
</p>

<p>
  <mat-form-field>
    <input matInput [matDatepicker]="dp3" placeholder="Input disabled" disabled>
    <mat-datepicker-toggle matSuffix [for]="dp3"></mat-datepicker-toggle>
    <mat-datepicker #dp3 disabled="false"></mat-datepicker>
  </mat-form-field>
</p>

 Now, see the typescript file.

import {Component} from '@angular/core';

/** @title Disabled datepicker */
@Component({
  selector: 'datepicker-disabled-example',
  templateUrl: 'datepicker-disabled-example.html',
  styleUrls: ['datepicker-disabled-example.css'],
})
export class DatepickerDisabledExample {}

That’s it for this tutorial. 

Source: https://appdividend.com/2022/02/16/angular-datepicker/

#angular

Einar  Hintz

Einar Hintz

1593229920

Android Menu - Steps to implement Menu in Android - DataFlair

Types of Android Menu

Let us see the various types of menu in Android:

1. Android Options Menu

The Options Menu is a collection of options for an activity. It has a set of items that are useful to perform actions. It helps us to combine multiple actions together.

Following is an example of Options Menu:

Options Menu in Android

2. PopUp Menu

Pop-Up menu is a menu that displays a list of items in a popup window. A pop-up menu appears below the view by default, in case there is no space, it appears above it.

Android Pop Up menu

3. Contextual Menu

A contextual menu is a floating menu. It appears only when the users long-press an element or right clicks on that. It generally affects the selected element.

Contextual menu

#android tutorials #android menu #android menu types #contextual menu #menu android #menu in android #options menu #types of menu in android