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flutter开发实战-实现自定义按钮类似UIButton效果

最近开发过程中需要实现一下UIButton效果的flutter按钮，这里使用的是监听手势点击事件。

一、GestureDetector

GestureDetector属性定义

GestureDetector({super.key,this.child,this.onTapDown,this.onTapUp,this.onTap,this.onTapCancel,this.onSecondaryTap,this.onSecondaryTapDown,this.onSecondaryTapUp,this.onSecondaryTapCancel,this.onTertiaryTapDown,this.onTertiaryTapUp,this.onTertiaryTapCancel,this.onDoubleTapDown,this.onDoubleTap,this.onDoubleTapCancel,this.onLongPressDown,this.onLongPressCancel,this.onLongPress,this.onLongPressStart,
...

由于属性太多，我们实现onTapDown、onTapUp、onTapCancel、onTap。

二、实现flutter自定义按钮

实现自定义按钮类似，我们实现onTapDown、onTapUp、onTapCancel、onTap这几个方法

return GestureDetector(onTapDown: handleTapDown,// 处理按下事件onTapUp: handleTapUp,// 处理抬起事件onTap: handleTap,onTapCancel: handleTapCancel,
}void handleTapDown(TapDownDetails details) {if (widget.enabled != null && widget.enabled == true) {setState(() {_highlighted = true;});}}void handleTapUp(TapUpDetails details) {setState(() {_highlighted = false;});}void handleTapCancel() {setState(() {_highlighted = false;});}void handleTap() {if (widget.enabled != null && widget.enabled == true) {setState(() {_highlighted = true;});Future.delayed(Duration(milliseconds: 100), () {if (mounted) {setState(() {_highlighted = false;});}});if (widget.enabled != null && widget.enabled == true) {widget.onPressed();}}}

完整代码如下

import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';//枚举类的声明
enum ButtonAlignment { Center, Left, Right }class ButtonWidget extends StatefulWidget {const ButtonWidget({Key? key,this.bgColor,this.bgHighlightedColor,this.color,this.highlightedColor,this.disableColor,this.bgDisableColor,this.width,this.height,this.borderRadius,this.buttonAlignment: ButtonAlignment.Center,this.text: "",this.textFontSize,this.icon,this.iconTextPadding,required this.onPressed,this.enabled = true,required this.child,this.border,this.padding,}) : super(key: key);final Color? bgColor; // 背景颜色final Color? bgHighlightedColor; // 背景点击高亮颜色final Color? color;final Color? highlightedColor;final Color? disableColor;final Color? bgDisableColor;final double? width;final double? height;final VoidCallback onPressed;final double? borderRadius;final ButtonAlignment? buttonAlignment;final String? text;final double? textFontSize;final Icon? icon;final double? iconTextPadding;final bool? enabled;final Widget child;final Border? border;final EdgeInsetsGeometry? padding;@override_ButtonWidgetState createState() => _ButtonWidgetState();
}class _ButtonWidgetState extends State<ButtonWidget> {bool _highlighted = false;@overridevoid initState() {// TODO: implement initStatesuper.initState();_highlighted = false;}void handleTapDown(TapDownDetails details) {if (widget.enabled != null && widget.enabled == true) {setState(() {_highlighted = true;});}}void handleTapUp(TapUpDetails details) {setState(() {_highlighted = false;});}void handleTapCancel() {setState(() {_highlighted = false;});}void handleTap() {if (widget.enabled != null && widget.enabled == true) {setState(() {_highlighted = true;});Future.delayed(Duration(milliseconds: 100), () {if (mounted) {setState(() {_highlighted = false;});}});if (widget.enabled != null && widget.enabled == true) {widget.onPressed();}}}AlignmentGeometry showAlignment(ButtonAlignment? buttonAlignment) {AlignmentGeometry alignment = Alignment.center;if (buttonAlignment != null) {if (buttonAlignment == ButtonAlignment.Left) {alignment = Alignment.centerLeft;} else if (buttonAlignment == ButtonAlignment.Right) {alignment = Alignment.centerRight;} else {alignment = Alignment.center;}}return alignment;}@overrideWidget build(BuildContext context) {return GestureDetector(onTapDown: handleTapDown,// 处理按下事件onTapUp: handleTapUp,// 处理抬起事件onTap: handleTap,onTapCancel: handleTapCancel,child: Container(padding: widget.padding,width: widget.width,height: widget.height,alignment: showAlignment(widget.buttonAlignment),decoration: BoxDecoration(color: boxDecorationBgColor(),borderRadius: BorderRadius.circular(widget.borderRadius ?? 0),border: widget.border),child: widget.child,),);}Color? boxDecorationBgColor() {if (widget.enabled != null && widget.enabled == true) {return (_highlighted ? widget.bgHighlightedColor : widget.bgColor);}return widget.bgDisableColor ?? widget.bgColor;}Color? textColor() {if (widget.enabled != null && widget.enabled == true) {return (_highlighted ? widget.highlightedColor : widget.color);}return widget.disableColor ?? widget.bgColor;}
}

三、小结

flutter开发实战-实现自定义按钮类似UIButton效果，通过监听手势GestureDetector的onTapDown、onTapUp、onTapCancel、onTap来实现按下背景变换，松开背景恢复默认等效果。

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