Android笔记:波纹按钮

转载学习自:菜鸟教程http://www.runoob.com

ImageView有两个可以设置图片的属性，分别是：src和background

常识：

①background通常指的都是背景,而src指的是内容!!

②当使用src填入图片时,是按照图片大小直接填充,并不会进行拉伸

而使用background填入图片,则是会根据ImageView给定的宽度来进行拉伸

  1 package com.example.administrator.testt;
  2 
  3 import android.content.Context;
  4 import android.graphics.Canvas;
  5 import android.graphics.Paint;
  6 import android.os.SystemClock;
  7 import android.util.AttributeSet;
  8 import android.view.MotionEvent;
  9 import android.view.ViewConfiguration;
 10 import android.widget.ImageButton;
 11 
 12 public class MyButton extends android.support.v7.widget.AppCompatImageButton {
 13     private static final int INVALIDATE_DURATION = 15; //每次刷新的时间间隔
 14     private static int DIFFUSE_GAP = 10; //扩散半径增量
 15     private static int TAP_TIMEOUT; //判断点击和长按的时间
 16 
 17     private int viewWIdth,viewHeight;   //控件宽高
 18     private int pointX,pointY;          //空间原点坐标(左上角)
 19     private int maxRadio;               //扩散的最大半径
 20     private int shaderRadio;            //扩散的半径
 21 
 22     private Paint bottomPaint, colorPaint;  //画笔:背景和水波纹
 23     private boolean isPushBUtton;       //记录是否被按下
 24 
 25     private int eventX, eventY;         //触摸位置的X,Y坐标
 26     private long downTime = 0;          //按下的时间
 27 
 28 
 29     public MyButton(Context context,AttributeSet attrs) {
 30         super(context,attrs);
 31         initPaint();
 32         TAP_TIMEOUT = ViewConfiguration.getLongPressTimeout(); //判断多久之后判定为长按
 33 
 34     }
 35 
 36 
 37     private void initPaint(){
 38         colorPaint = new Paint();
 39         bottomPaint = new Paint();
 40         colorPaint.setColor(getResources().getColor(R.color.reveal_color,null));
 41         //getResources().getColor(int id)已过时,现已被getColor(int id,Theme theme)代替,theme可用null
 42         bottomPaint.setColor(getResources().getColor(R.color.bottom_color,null));
 43 
 44     }
 45 
 46     @Override
 47     public boolean onTouchEvent(MotionEvent event) {
 48         switch (event.getAction()){
 49             case MotionEvent.ACTION_DOWN:
 50                 if(downTime == 0)downTime = SystemClock.elapsedRealtime();
 51                 eventX = (int) event.getX();
 52                 eventY = (int) event.getY(); //获取点击的XY坐标
 53                 //计算最大半径
 54                 countMaxRadio();
 55                 isPushBUtton = true; //确认已被按下
 56                 postInvalidateDelayed(INVALIDATE_DURATION);
 57                 break;
 58             case MotionEvent.ACTION_UP:
 59             case MotionEvent.ACTION_CANCEL:
 60                 if (SystemClock.elapsedRealtime() - downTime < TAP_TIMEOUT) {
 61                     DIFFUSE_GAP = 30;       //扩散半径增量
 62                     postInvalidate();       //刷新界面
 63                 } else {
 64                     clearData();
 65                 }
 66                 break;
 67         }
 68 
 69         return super.onTouchEvent(event);
 70     }
 71 
 72     @Override
 73     protected void dispatchDraw(Canvas canvas) {
 74         super.dispatchDraw(canvas);
 75         if(!isPushBUtton) return; //如果按钮没有被按下则返回
 76         //绘制按下后的整个背景
 77         canvas.drawRect(pointX, pointY, pointX + viewWIdth, pointY + viewHeight, bottomPaint);
 78         canvas.save();
 79         //绘制扩散圆形背景
 80         canvas.drawCircle(eventX,eventY,shaderRadio,colorPaint);
 81         canvas.restore();
 82         //直到半径等于最大半径
 83         if(shaderRadio < maxRadio){
 84             postInvalidateDelayed(INVALIDATE_DURATION,
 85                     pointX, pointY, pointX + viewWIdth, pointY + viewHeight);
 86             shaderRadio += DIFFUSE_GAP;
 87         }else{
 88             clearData();
 89         }
 90     }
 91 
 92     private void countMaxRadio(){
 93         if (viewWIdth > viewHeight) {
 94             if (eventX < viewWIdth / 2) {
 95                 maxRadio = viewWIdth - eventX;
 96             } else {
 97                 maxRadio = viewWIdth / 2 + eventX;
 98             }
 99         } else {
100             if (eventY < viewHeight / 2) {
101                 maxRadio = viewHeight - eventY;
102             } else {
103                 maxRadio = viewHeight / 2 + eventY;
104             }
105         }
106 
107     }
108 
109     private void clearData(){
110         downTime = 0;
111         DIFFUSE_GAP = 10;
112         isPushBUtton = false;
113         shaderRadio = 0; //扩散的半径
114         postInvalidate();   //刷新界面
115 
116     }
117 
118     @Override
119     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
120         super.onSizeChanged(w, h, oldw, oldh);
121         this.viewWIdth = w;
122         this.viewHeight = h;
123     }
124 }

ImageButton和Button的区别:

A.ImageButton用图像来表现按钮;

设置方式:android:src="img_id"

android:src="@drawable/ic_launcher_background"

B.ImageButton控件的Click事件是配合System.Web.UI.ImageClickEventHandler委托工作的,ImageButton可获取所点击的X,Y坐标,详情见例子.