| // Copyright 2015 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| import 'dart:ui' as ui; |
| |
| import 'package:flutter/foundation.dart'; |
| |
| import 'basic.dart'; |
| import 'framework.dart'; |
| |
| /// Whether in portrait or landscape. |
| enum Orientation { |
| /// Taller than wide. |
| portrait, |
| |
| /// Wider than tall. |
| landscape |
| } |
| |
| /// Information about a piece of media (e.g., a window). |
| /// |
| /// For example, the [MediaQueryData.size] property contains the width and |
| /// height of the current window. |
| /// |
| /// To obtain the current [MediaQueryData] for a given [BuildContext], use the |
| /// [MediaQuery.of] function. For example, to obtain the size of the current |
| /// window, use `MediaQuery.of(context).size`. |
| /// |
| /// If no [MediaQuery] is in scope then the [MediaQuery.of] method will throw an |
| /// exception, unless the `nullOk` argument is set to true, in which case it |
| /// returns null. |
| @immutable |
| class MediaQueryData { |
| /// Creates data for a media query with explicit values. |
| /// |
| /// Consider using [MediaQueryData.fromWindow] to create data based on a |
| /// [Window]. |
| const MediaQueryData({ |
| this.size: Size.zero, |
| this.devicePixelRatio: 1.0, |
| this.textScaleFactor: 1.0, |
| this.padding: EdgeInsets.zero, |
| this.alwaysUse24HourFormat: false, |
| }); |
| |
| /// Creates data for a media query based on the given window. |
| /// |
| /// If you use this, you should ensure that you also register for |
| /// notifications so that you can update your [MediaQueryData] when the |
| /// window's metrics change. For example, see |
| /// [WidgetsBindingObserver.didChangeMetrics] or [Window.onMetricsChanged]. |
| MediaQueryData.fromWindow(ui.Window window) |
| : size = window.physicalSize / window.devicePixelRatio, |
| devicePixelRatio = window.devicePixelRatio, |
| textScaleFactor = window.textScaleFactor, |
| padding = new EdgeInsets.fromWindowPadding(window.padding, window.devicePixelRatio), |
| alwaysUse24HourFormat = window.alwaysUse24HourFormat; |
| |
| /// The size of the media in logical pixel (e.g, the size of the screen). |
| /// |
| /// Logical pixels are roughly the same visual size across devices. Physical |
| /// pixels are the size of the actual hardware pixels on the device. The |
| /// number of physical pixels per logical pixel is described by the |
| /// [devicePixelRatio]. |
| final Size size; |
| |
| /// The number of device pixels for each logical pixel. This number might not |
| /// be a power of two. Indeed, it might not even be an integer. For example, |
| /// the Nexus 6 has a device pixel ratio of 3.5. |
| final double devicePixelRatio; |
| |
| /// The number of font pixels for each logical pixel. |
| /// |
| /// For example, if the text scale factor is 1.5, text will be 50% larger than |
| /// the specified font size. |
| final double textScaleFactor; |
| |
| /// The padding around the edges of the media (e.g., the screen). |
| final EdgeInsets padding; |
| |
| /// Whether to use 24-hour format when formatting time. |
| /// |
| /// The behavior of this flag is different across platforms: |
| /// |
| /// - On Android this flag is reported directly from the user settings called |
| /// "Use 24-hour format". It applies to any locale used by the application, |
| /// whether it is the system-wide locale, or the custom locale set by the |
| /// application. |
| /// - On iOS this flag is set to true when the user setting called "24-Hour |
| /// Time" is set or the system-wide locale's default uses 24-hour |
| /// formatting. |
| final bool alwaysUse24HourFormat; |
| |
| /// The orientation of the media (e.g., whether the device is in landscape or portrait mode). |
| Orientation get orientation { |
| return size.width > size.height ? Orientation.landscape : Orientation.portrait; |
| } |
| |
| /// Creates a copy of this media query data but with the given fields replaced |
| /// with the new values. |
| MediaQueryData copyWith({ |
| Size size, |
| double devicePixelRatio, |
| double textScaleFactor, |
| EdgeInsets padding, |
| }) { |
| return new MediaQueryData( |
| size: size ?? this.size, |
| devicePixelRatio: devicePixelRatio ?? this.devicePixelRatio, |
| textScaleFactor: textScaleFactor ?? this.textScaleFactor, |
| padding: padding ?? this.padding, |
| ); |
| } |
| |
| /// Creates a copy of this media query data but with the given paddings |
| /// replaced with zero. |
| /// |
| /// The `removeLeft`, `removeTop`, `removeRight`, and `removeBottom` arguments |
| /// must not be null. If all four are false (the default) then this |
| /// [MediaQueryData] is returned unmodified. |
| /// |
| /// See also: |
| /// |
| /// * [new MediaQuery.removePadding], which uses this method to remove padding |
| /// from the ambient [MediaQuery]. |
| /// * [SafeArea], which both removes the padding from the [MediaQuery] and |
| /// adds a [Padding] widget. |
| MediaQueryData removePadding({ |
| bool removeLeft: false, |
| bool removeTop: false, |
| bool removeRight: false, |
| bool removeBottom: false, |
| }) { |
| if (!(removeLeft || removeTop || removeRight || removeBottom)) |
| return this; |
| return new MediaQueryData( |
| size: size, |
| devicePixelRatio: devicePixelRatio, |
| textScaleFactor: textScaleFactor, |
| padding: padding.copyWith( |
| left: removeLeft ? 0.0 : null, |
| top: removeTop ? 0.0 : null, |
| right: removeRight ? 0.0 : null, |
| bottom: removeBottom ? 0.0 : null, |
| ), |
| ); |
| } |
| |
| @override |
| bool operator ==(Object other) { |
| if (other.runtimeType != runtimeType) |
| return false; |
| final MediaQueryData typedOther = other; |
| return typedOther.size == size |
| && typedOther.devicePixelRatio == devicePixelRatio |
| && typedOther.textScaleFactor == textScaleFactor |
| && typedOther.padding == padding; |
| } |
| |
| @override |
| int get hashCode => hashValues(size, devicePixelRatio, textScaleFactor, padding); |
| |
| @override |
| String toString() { |
| return '$runtimeType(size: $size, devicePixelRatio: $devicePixelRatio, ' |
| 'textScaleFactor: $textScaleFactor, padding: $padding)'; |
| } |
| } |
| |
| /// Establishes a subtree in which media queries resolve to the given data. |
| /// |
| /// For example, to learn the size of the current media (e.g., the window |
| /// containing your app), you can read the [MediaQueryData.size] property from |
| /// the [MediaQueryData] returned by [MediaQuery.of]: |
| /// `MediaQuery.of(context).size`. |
| /// |
| /// Querying the current media using [MediaQuery.of] will cause your widget to |
| /// rebuild automatically whenever the [MediaQueryData] changes (e.g., if the |
| /// user rotates their device). |
| /// |
| /// If no [MediaQuery] is in scope then the [MediaQuery.of] method will throw an |
| /// exception, unless the `nullOk` argument is set to true, in which case it |
| /// returns null. |
| /// |
| /// See also: |
| /// |
| /// * [WidgetsApp] and [MaterialApp], which introduce a [MediaQuery] and keep |
| /// it up to date with the current screen metrics as they change. |
| /// * [MediaQueryData], the data structure that represents the metrics. |
| class MediaQuery extends InheritedWidget { |
| /// Creates a widget that provides [MediaQueryData] to its descendants. |
| /// |
| /// The [data] and [child] arguments must not be null. |
| const MediaQuery({ |
| Key key, |
| @required this.data, |
| @required Widget child, |
| }) : assert(child != null), |
| assert(data != null), |
| super(key: key, child: child); |
| |
| /// Creates a new [MediaQuery] that inherits from the ambient [MediaQuery] from |
| /// the given context, but removes the specified paddings. |
| /// |
| /// The [context] argument is required, must not be null, and must have a |
| /// [MediaQuery] in scope. |
| /// |
| /// The `removeLeft`, `removeTop`, `removeRight`, and `removeBottom` arguments |
| /// must not be null. If all four are false (the default) then the returned |
| /// [MediaQuery] reuses the ambient [MediaQueryData] unmodified, which is not |
| /// particularly useful. |
| /// |
| /// The [child] argument is required and must not be null. |
| /// |
| /// See also: |
| /// |
| /// * [SafeArea], which both removes the padding from the [MediaQuery] and |
| /// adds a [Padding] widget. |
| factory MediaQuery.removePadding({ |
| Key key, |
| @required BuildContext context, |
| bool removeLeft: false, |
| bool removeTop: false, |
| bool removeRight: false, |
| bool removeBottom: false, |
| @required Widget child, |
| }) { |
| return new MediaQuery( |
| key: key, |
| data: MediaQuery.of(context).removePadding( |
| removeLeft: removeLeft, |
| removeTop: removeTop, |
| removeRight: removeRight, |
| removeBottom: removeBottom, |
| ), |
| child: child, |
| ); |
| } |
| |
| /// Contains information about the current media. |
| /// |
| /// For example, the [MediaQueryData.size] property contains the width and |
| /// height of the current window. |
| final MediaQueryData data; |
| |
| /// The data from the closest instance of this class that encloses the given |
| /// context. |
| /// |
| /// You can use this function to query the size an orientation of the screen. |
| /// When that information changes, your widget will be scheduled to be rebuilt, |
| /// keeping your widget up-to-date. |
| /// |
| /// Typical usage is as follows: |
| /// |
| /// ```dart |
| /// MediaQueryData media = MediaQuery.of(context); |
| /// ``` |
| /// |
| /// If there is no [MediaQuery] in scope, then this will throw an exception. |
| /// To return null if there is no [MediaQuery], then pass `nullOk: true`. |
| /// |
| /// If you use this from a widget (e.g. in its build function), consider |
| /// calling [debugCheckHasMediaQuery]. |
| static MediaQueryData of(BuildContext context, { bool nullOk: false }) { |
| assert(context != null); |
| assert(nullOk != null); |
| final MediaQuery query = context.inheritFromWidgetOfExactType(MediaQuery); |
| if (query != null) |
| return query.data; |
| if (nullOk) |
| return null; |
| throw new FlutterError( |
| 'MediaQuery.of() called with a context that does not contain a MediaQuery.\n' |
| 'No MediaQuery ancestor could be found starting from the context that was passed ' |
| 'to MediaQuery.of(). This can happen because you do not have a WidgetsApp or ' |
| 'MaterialApp widget (those widgets introduce a MediaQuery), or it can happen ' |
| 'if the context you use comes from a widget above those widgets.\n' |
| 'The context used was:\n' |
| ' $context' |
| ); |
| } |
| |
| @override |
| bool updateShouldNotify(MediaQuery old) => data != old.data; |
| |
| @override |
| void debugFillProperties(DiagnosticPropertiesBuilder description) { |
| super.debugFillProperties(description); |
| description.add(new DiagnosticsProperty<MediaQueryData>('data', data, showName: false)); |
| } |
| } |