学习日报

自定义ImageButton：MyButton.java

package demo.com.jay.buttondemo;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.SystemClock;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ViewConfiguration;
import android.widget.ImageButton;

/**
 * Created by coder-pig on 2015/7/16 0016.
 */
public class MyButton extends ImageButton {


    private static final int INVALIDATE_DURATION = 15;     //每次刷新的时间间隔
    private static int DIFFUSE_GAP = 10;                  //扩散半径增量
    private static int TAP_TIMEOUT;                         //判断点击和长按的时间

    private int viewWidth, viewHeight;                   //控件宽高
    private int pointX, pointY;                          //控件原点坐标（左上角）
    private int maxRadio;                             //扩散的最大半径
    private int shaderRadio;                        //扩散的半径

    private Paint bottomPaint, colorPaint;          //画笔:背景和水波纹
    private boolean isPushButton;                 //记录是否按钮被按下

    private int eventX, eventY;                  //触摸位置的X,Y坐标
    private long downTime = 0;                 //按下的时间


    public MyButton(Context context, AttributeSet attrs) {
        super(context, attrs);
        initPaint();
        TAP_TIMEOUT = ViewConfiguration.getLongPressTimeout();
    }


    /*
    * 初始化画笔
    * */
    private void initPaint() {
        colorPaint = new Paint();
        bottomPaint = new Paint();
        colorPaint.setColor(getResources().getColor(R.color.reveal_color));
        bottomPaint.setColor(getResources().getColor(R.color.bottom_color));
    }


    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                if (downTime == 0) downTime = SystemClock.elapsedRealtime();
                eventX = (int) event.getX();
                eventY = (int) event.getY();
                //计算最大半径：
                countMaxRadio();
                isPushButton = true;
                postInvalidateDelayed(INVALIDATE_DURATION);
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                if(SystemClock.elapsedRealtime() - downTime < TAP_TIMEOUT){
                    DIFFUSE_GAP = 30;
                    postInvalidate();
                }else{
                    clearData();
                }
                break;
        }
        return super.onTouchEvent(event);
    }


    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(canvas);
        if(!isPushButton) return; //如果按钮没有被按下则返回
        //绘制按下后的整个背景
        canvas.drawRect(pointX, pointY, pointX + viewWidth, pointY + viewHeight, bottomPaint);
        canvas.save();
        //绘制扩散圆形背景
        canvas.clipRect(pointX, pointY, pointX + viewWidth, pointY + viewHeight);
        canvas.drawCircle(eventX, eventY, shaderRadio, colorPaint);
        canvas.restore();//直到半径等于最大半径if(shaderRadio < maxRadio){
            postInvalidateDelayed(INVALIDATE_DURATION,
                    pointX, pointY, pointX + viewWidth, pointY + viewHeight);
            shaderRadio += DIFFUSE_GAP;}else{
            clearData();}}/*
        * 计算最大半径的方法
        * */privatevoid countMaxRadio(){if(viewWidth > viewHeight){if(eventX < viewWidth /2){
                maxRadio = viewWidth - eventX;}else{
                maxRadio = viewWidth /2+ eventX;}}else{if(eventY < viewHeight /2){
                maxRadio = viewHeight - eventY;}else{
                maxRadio = viewHeight /2+ eventY;}}}/*
    * 重置数据的方法
    * */privatevoid clearData(){
        downTime =0;
        DIFFUSE_GAP =10;
        isPushButton =false;
        shaderRadio =0;
        postInvalidate();}@Overrideprotectedvoid onSizeChanged(int w,int h,int oldw,int oldh){super.onSizeChanged(w, h, oldw, oldh);this.viewWidth = w;this.viewHeight = h;}}