packages/flutter/lib/src/material/circle_avatar.dart - mirrors/flutter - Git at Google

 // Copyright 2014 The Flutter 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 'package:flutter/widgets.dart';

 import 'constants.dart';
 import 'theme.dart';
 import 'theme_data.dart';

 // Examples can assume:
 // String userAvatarUrl;

 /// A circle that represents a user.
 ///
 /// Typically used with a user's profile image, or, in the absence of
 /// such an image, the user's initials. A given user's initials should
 /// always be paired with the same background color, for consistency.
 ///
 /// The [onBackgroundImageError] parameter must be null if the [backgroundImage]
 /// is null.
 ///
 /// {@tool snippet}
 ///
 /// If the avatar is to have an image, the image should be specified in the
 /// [backgroundImage] property:
 ///
 /// ```dart
 /// CircleAvatar(
 ///   backgroundImage: NetworkImage(userAvatarUrl),
 /// )
 /// ```
 /// {@end-tool}
 ///
 /// The image will be cropped to have a circle shape.
 ///
 /// {@tool snippet}
 ///
 /// If the avatar is to just have the user's initials, they are typically
 /// provided using a [Text] widget as the [child] and a [backgroundColor]:
 ///
 /// ```dart
 /// CircleAvatar(
 ///   backgroundColor: Colors.brown.shade800,
 ///   child: Text('AH'),
 /// )
 /// ```
 /// {@end-tool}
 ///
 /// See also:
 ///
 ///  * [Chip], for representing users or concepts in long form.
 ///  * [ListTile], which can combine an icon (such as a [CircleAvatar]) with
 ///    some text for a fixed height list entry.
 ///  * <https://material.io/design/components/chips.html#input-chips>
 class CircleAvatar extends StatelessWidget {
   /// Creates a circle that represents a user.
   const CircleAvatar({
     Key key,
     this.child,
     this.backgroundColor,
     this.backgroundImage,
     this.onBackgroundImageError,
     this.foregroundColor,
     this.radius,
     this.minRadius,
     this.maxRadius,
   }) : assert(radius == null || (minRadius == null && maxRadius == null)),
        assert(backgroundImage != null || onBackgroundImageError == null),
        super(key: key);

   /// The widget below this widget in the tree.
   ///
   /// Typically a [Text] widget. If the [CircleAvatar] is to have an image, use
   /// [backgroundImage] instead.
   final Widget child;

   /// The color with which to fill the circle. Changing the background
   /// color will cause the avatar to animate to the new color.
   ///
   /// If a [backgroundColor] is not specified, the theme's
   /// [ThemeData.primaryColorLight] is used with dark foreground colors, and
   /// [ThemeData.primaryColorDark] with light foreground colors.
   final Color backgroundColor;

   /// The default text color for text in the circle.
   ///
   /// Defaults to the primary text theme color if no [backgroundColor] is
   /// specified.
   ///
   /// Defaults to [ThemeData.primaryColorLight] for dark background colors, and
   /// [ThemeData.primaryColorDark] for light background colors.
   final Color foregroundColor;

   /// The background image of the circle. Changing the background
   /// image will cause the avatar to animate to the new image.
   ///
   /// If the [CircleAvatar] is to have the user's initials, use [child] instead.
   final ImageProvider backgroundImage;

   /// An optional error callback for errors emitted when loading
   /// [backgroundImage].
   final ImageErrorListener onBackgroundImageError;

   /// The size of the avatar, expressed as the radius (half the diameter).
   ///
   /// If [radius] is specified, then neither [minRadius] nor [maxRadius] may be
   /// specified. Specifying [radius] is equivalent to specifying a [minRadius]
   /// and [maxRadius], both with the value of [radius].
   ///
   /// If neither [minRadius] nor [maxRadius] are specified, defaults to 20
   /// logical pixels. This is the appropriate size for use with
   /// [ListTile.leading].
   ///
   /// Changes to the [radius] are animated (including changing from an explicit
   /// [radius] to a [minRadius]/[maxRadius] pair or vice versa).
   final double radius;

   /// The minimum size of the avatar, expressed as the radius (half the
   /// diameter).
   ///
   /// If [minRadius] is specified, then [radius] must not also be specified.
   ///
   /// Defaults to zero.
   ///
   /// Constraint changes are animated, but size changes due to the environment
   /// itself changing are not. For example, changing the [minRadius] from 10 to
   /// 20 when the [CircleAvatar] is in an unconstrained environment will cause
   /// the avatar to animate from a 20 pixel diameter to a 40 pixel diameter.
   /// However, if the [minRadius] is 40 and the [CircleAvatar] has a parent
   /// [SizedBox] whose size changes instantaneously from 20 pixels to 40 pixels,
   /// the size will snap to 40 pixels instantly.
   final double minRadius;

   /// The maximum size of the avatar, expressed as the radius (half the
   /// diameter).
   ///
   /// If [maxRadius] is specified, then [radius] must not also be specified.
   ///
   /// Defaults to [double.infinity].
   ///
   /// Constraint changes are animated, but size changes due to the environment
   /// itself changing are not. For example, changing the [maxRadius] from 10 to
   /// 20 when the [CircleAvatar] is in an unconstrained environment will cause
   /// the avatar to animate from a 20 pixel diameter to a 40 pixel diameter.
   /// However, if the [maxRadius] is 40 and the [CircleAvatar] has a parent
   /// [SizedBox] whose size changes instantaneously from 20 pixels to 40 pixels,
   /// the size will snap to 40 pixels instantly.
   final double maxRadius;

   // The default radius if nothing is specified.
   static const double _defaultRadius = 20.0;

   // The default min if only the max is specified.
   static const double _defaultMinRadius = 0.0;

   // The default max if only the min is specified.
   static const double _defaultMaxRadius = double.infinity;

   double get _minDiameter {
     if (radius == null && minRadius == null && maxRadius == null) {
       return _defaultRadius * 2.0;
     }
     return 2.0 * (radius ?? minRadius ?? _defaultMinRadius);
   }

   double get _maxDiameter {
     if (radius == null && minRadius == null && maxRadius == null) {
       return _defaultRadius * 2.0;
     }
     return 2.0 * (radius ?? maxRadius ?? _defaultMaxRadius);
   }

   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMediaQuery(context));
     final ThemeData theme = Theme.of(context);
     TextStyle textStyle = theme.primaryTextTheme.subtitle1.copyWith(color: foregroundColor);
     Color effectiveBackgroundColor = backgroundColor;
     if (effectiveBackgroundColor == null) {
       switch (ThemeData.estimateBrightnessForColor(textStyle.color)) {
         case Brightness.dark:
           effectiveBackgroundColor = theme.primaryColorLight;
           break;
         case Brightness.light:
           effectiveBackgroundColor = theme.primaryColorDark;
           break;
       }
     } else if (foregroundColor == null) {
       switch (ThemeData.estimateBrightnessForColor(backgroundColor)) {
         case Brightness.dark:
           textStyle = textStyle.copyWith(color: theme.primaryColorLight);
           break;
         case Brightness.light:
           textStyle = textStyle.copyWith(color: theme.primaryColorDark);
           break;
       }
     }
     final double minDiameter = _minDiameter;
     final double maxDiameter = _maxDiameter;
     return AnimatedContainer(
       constraints: BoxConstraints(
         minHeight: minDiameter,
         minWidth: minDiameter,
         maxWidth: maxDiameter,
         maxHeight: maxDiameter,
       ),
       duration: kThemeChangeDuration,
       decoration: BoxDecoration(
         color: effectiveBackgroundColor,
         image: backgroundImage != null
           ? DecorationImage(
               image: backgroundImage,
               onError: onBackgroundImageError,
               fit: BoxFit.cover,
             )
           : null,
         shape: BoxShape.circle,
       ),
       child: child == null
           ? null
           : Center(
               child: MediaQuery(
                 // Need to ignore the ambient textScaleFactor here so that the
                 // text doesn't escape the avatar when the textScaleFactor is large.
                 data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
                 child: IconTheme(
                   data: theme.iconTheme.copyWith(color: textStyle.color),
                   child: DefaultTextStyle(
                     style: textStyle,
                     child: child,
                   ),
                 ),
               ),
             ),
     );
   }
 }
	// Copyright 2014 The Flutter 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 'package:flutter/widgets.dart';

	import 'constants.dart';
	import 'theme.dart';
	import 'theme_data.dart';

	// Examples can assume:
	// String userAvatarUrl;

	/// A circle that represents a user.
	///
	/// Typically used with a user's profile image, or, in the absence of
	/// such an image, the user's initials. A given user's initials should
	/// always be paired with the same background color, for consistency.
	///
	/// The [onBackgroundImageError] parameter must be null if the [backgroundImage]
	/// is null.
	///
	/// {@tool snippet}
	///
	/// If the avatar is to have an image, the image should be specified in the
	/// [backgroundImage] property:
	///
	/// ```dart
	/// CircleAvatar(
	/// backgroundImage: NetworkImage(userAvatarUrl),
	/// )
	/// ```
	/// {@end-tool}
	///
	/// The image will be cropped to have a circle shape.
	///
	/// {@tool snippet}
	///
	/// If the avatar is to just have the user's initials, they are typically
	/// provided using a [Text] widget as the [child] and a [backgroundColor]:
	///
	/// ```dart
	/// CircleAvatar(
	/// backgroundColor: Colors.brown.shade800,
	/// child: Text('AH'),
	/// )
	/// ```
	/// {@end-tool}
	///
	/// See also:
	///
	/// * [Chip], for representing users or concepts in long form.
	/// * [ListTile], which can combine an icon (such as a [CircleAvatar]) with
	/// some text for a fixed height list entry.
	/// * <https://material.io/design/components/chips.html#input-chips>
	class CircleAvatar extends StatelessWidget {
	/// Creates a circle that represents a user.
	const CircleAvatar({
	Key key,
	this.child,
	this.backgroundColor,
	this.backgroundImage,
	this.onBackgroundImageError,
	this.foregroundColor,
	this.radius,
	this.minRadius,
	this.maxRadius,
	}) : assert(radius == null \|\| (minRadius == null && maxRadius == null)),
	assert(backgroundImage != null \|\| onBackgroundImageError == null),
	super(key: key);

	/// The widget below this widget in the tree.
	///
	/// Typically a [Text] widget. If the [CircleAvatar] is to have an image, use
	/// [backgroundImage] instead.
	final Widget child;

	/// The color with which to fill the circle. Changing the background
	/// color will cause the avatar to animate to the new color.
	///
	/// If a [backgroundColor] is not specified, the theme's
	/// [ThemeData.primaryColorLight] is used with dark foreground colors, and
	/// [ThemeData.primaryColorDark] with light foreground colors.
	final Color backgroundColor;

	/// The default text color for text in the circle.
	///
	/// Defaults to the primary text theme color if no [backgroundColor] is
	/// specified.
	///
	/// Defaults to [ThemeData.primaryColorLight] for dark background colors, and
	/// [ThemeData.primaryColorDark] for light background colors.
	final Color foregroundColor;

	/// The background image of the circle. Changing the background
	/// image will cause the avatar to animate to the new image.
	///
	/// If the [CircleAvatar] is to have the user's initials, use [child] instead.
	final ImageProvider backgroundImage;

	/// An optional error callback for errors emitted when loading
	/// [backgroundImage].
	final ImageErrorListener onBackgroundImageError;

	/// The size of the avatar, expressed as the radius (half the diameter).
	///
	/// If [radius] is specified, then neither [minRadius] nor [maxRadius] may be
	/// specified. Specifying [radius] is equivalent to specifying a [minRadius]
	/// and [maxRadius], both with the value of [radius].
	///
	/// If neither [minRadius] nor [maxRadius] are specified, defaults to 20
	/// logical pixels. This is the appropriate size for use with
	/// [ListTile.leading].
	///
	/// Changes to the [radius] are animated (including changing from an explicit
	/// [radius] to a [minRadius]/[maxRadius] pair or vice versa).
	final double radius;

	/// The minimum size of the avatar, expressed as the radius (half the
	/// diameter).
	///
	/// If [minRadius] is specified, then [radius] must not also be specified.
	///
	/// Defaults to zero.
	///
	/// Constraint changes are animated, but size changes due to the environment
	/// itself changing are not. For example, changing the [minRadius] from 10 to
	/// 20 when the [CircleAvatar] is in an unconstrained environment will cause
	/// the avatar to animate from a 20 pixel diameter to a 40 pixel diameter.
	/// However, if the [minRadius] is 40 and the [CircleAvatar] has a parent
	/// [SizedBox] whose size changes instantaneously from 20 pixels to 40 pixels,
	/// the size will snap to 40 pixels instantly.
	final double minRadius;

	/// The maximum size of the avatar, expressed as the radius (half the
	/// diameter).
	///
	/// If [maxRadius] is specified, then [radius] must not also be specified.
	///
	/// Defaults to [double.infinity].
	///
	/// Constraint changes are animated, but size changes due to the environment
	/// itself changing are not. For example, changing the [maxRadius] from 10 to
	/// 20 when the [CircleAvatar] is in an unconstrained environment will cause
	/// the avatar to animate from a 20 pixel diameter to a 40 pixel diameter.
	/// However, if the [maxRadius] is 40 and the [CircleAvatar] has a parent
	/// [SizedBox] whose size changes instantaneously from 20 pixels to 40 pixels,
	/// the size will snap to 40 pixels instantly.
	final double maxRadius;

	// The default radius if nothing is specified.
	static const double _defaultRadius = 20.0;

	// The default min if only the max is specified.
	static const double _defaultMinRadius = 0.0;

	// The default max if only the min is specified.
	static const double _defaultMaxRadius = double.infinity;

	double get _minDiameter {
	if (radius == null && minRadius == null && maxRadius == null) {
	return _defaultRadius * 2.0;
	}
	return 2.0 * (radius ?? minRadius ?? _defaultMinRadius);
	}

	double get _maxDiameter {
	if (radius == null && minRadius == null && maxRadius == null) {
	return _defaultRadius * 2.0;
	}
	return 2.0 * (radius ?? maxRadius ?? _defaultMaxRadius);
	}

	@override
	Widget build(BuildContext context) {
	assert(debugCheckHasMediaQuery(context));
	final ThemeData theme = Theme.of(context);
	TextStyle textStyle = theme.primaryTextTheme.subtitle1.copyWith(color: foregroundColor);
	Color effectiveBackgroundColor = backgroundColor;
	if (effectiveBackgroundColor == null) {
	switch (ThemeData.estimateBrightnessForColor(textStyle.color)) {
	case Brightness.dark:
	effectiveBackgroundColor = theme.primaryColorLight;
	break;
	case Brightness.light:
	effectiveBackgroundColor = theme.primaryColorDark;
	break;
	}
	} else if (foregroundColor == null) {
	switch (ThemeData.estimateBrightnessForColor(backgroundColor)) {
	case Brightness.dark:
	textStyle = textStyle.copyWith(color: theme.primaryColorLight);
	break;
	case Brightness.light:
	textStyle = textStyle.copyWith(color: theme.primaryColorDark);
	break;
	}
	}
	final double minDiameter = _minDiameter;
	final double maxDiameter = _maxDiameter;
	return AnimatedContainer(
	constraints: BoxConstraints(
	minHeight: minDiameter,
	minWidth: minDiameter,
	maxWidth: maxDiameter,
	maxHeight: maxDiameter,
	),
	duration: kThemeChangeDuration,
	decoration: BoxDecoration(
	color: effectiveBackgroundColor,
	image: backgroundImage != null
	? DecorationImage(
	image: backgroundImage,
	onError: onBackgroundImageError,
	fit: BoxFit.cover,
	)
	: null,
	shape: BoxShape.circle,
	),
	child: child == null
	? null
	: Center(
	child: MediaQuery(
	// Need to ignore the ambient textScaleFactor here so that the
	// text doesn't escape the avatar when the textScaleFactor is large.
	data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
	child: IconTheme(
	data: theme.iconTheme.copyWith(color: textStyle.color),
	child: DefaultTextStyle(
	style: textStyle,
	child: child,
	),
	),
	),
	),
	);
	}
	}