Android自定义控件实现水波纹效果

本文实例为大家分享了android自定义控件实现水波纹的具体代码，供大家参考，具体内容如下

示例代码：

mainactivity.java

package com.example.mhy.shuibowen;
 
import android.support.v7.app.appcompatactivity;
import android.os.bundle;
 
public class mainactivity extends appcompatactivity {
 
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);
  }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
 
  tools:context="com.example.mhy.shuibowen.mainactivity">
 
  <com.example.mhy.shuibowen.myringwave
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    />
</relativelayout>

myringwave.java

package com.example.mhy.shuibowen;
 
import android.content.context;
import android.graphics.canvas;
import android.graphics.color;
import android.graphics.paint;
import android.os.handler;
import android.util.attributeset;
import android.view.motionevent;
import android.view.view;
 
import java.util.arraylist;
 
/**
 * 水波纹效果
 * created by mhy on 2016/6/16.
 */
public class myringwave extends view {
  /**
   * 二个相临波浪中心点的最小距离
   */
  private static final int dis_solp = 13;
  protected boolean isrunning = false;
 
  private arraylist<wave> wlist;
 
  public myringwave(context context,attributeset attrs) {
    super(context, attrs);
    wlist = new arraylist<myringwave.wave>();
  }
 
  @override
  protected void ondraw(canvas canvas) {
    for(int i=0; i<wlist.size(); i++) {
      wave wave = wlist.get(i);
      canvas.drawcircle(wave.cx, wave.cy, wave.r, wave.p);
    }
  }
 
  @override
  public boolean ontouchevent(motionevent event) {
    super.ontouchevent(event);
 
    switch(event.getaction()) {
      case motionevent.action_down:
      case motionevent.action_move:
 
        int x = (int) event.getx();
        int y = (int) event.gety();
 
        addpoint(x, y);
 
        break;
      default:
        break;
    }
    return true;
  }
 
  private handler handler = new handler(){
    public void handlemessage(android.os.message msg) {
 
      //刷新数据
      flushdata();
      //刷新页面
      invalidate();
      //循环动画
      if (isrunning) {
        handler.sendemptymessagedelayed(0, 50);
      }
 
    }
  };
 
  /**
   * 刷新数据
   */
  private void flushdata() {
 
    for (int i = 0; i < wlist.size(); i++) {
 
      wave w = wlist.get(i);
 
      //如果透明度为 0 从集合中删除
      int alpha = w.p.getalpha();
      if(alpha == 0){
        wlist.remove(i); //删除i 以后，i的值应该再减1 否则会漏掉一个对象，不过，在此处影响不大，效果上看不出来。
        continue;
      }
 
      alpha-=5;
      if(alpha<5){
        alpha =0;
      }
      //降低透明度
      w.p.setalpha(alpha);
 
      //扩大半径
      w.r = w.r+3;
      //设置半径厚度
      w.p.setstrokewidth(w.r/3);
    }
 
 /*
  * 如果集合被清空，就停止刷新动画
  */
    if(wlist.size() == 0){
      isrunning = false;
    }
  }
 
  /**
   * 添加新的波浪中心点
   * @param x
   * @param y
   */
  private void addpoint(int x, int y) {
 
    if(wlist.size() == 0) {
      addpoint2list(x, y);
      isrunning = true;
      handler.sendemptymessage(0);
    }else{
      wave w = wlist.get(wlist.size()-1);
 
      if(math.abs(w.cx - x)>dis_solp || math.abs(w.cy-y)>dis_solp){
        addpoint2list(x,y);
      }
 
    };
  }
 
  /**
   * 添加新的波浪
   * @param x
   * @param y
   */
  private void addpoint2list(int x, int y) {
    wave w = new wave();
    w.cx = x;
    w.cy=y;
    paint pa=new paint();
    pa.setcolor(colors[(int)(math.random()*4)]);
    pa.setantialias(true);
    pa.setstyle(paint.style.stroke);
 
    w.p = pa;
 
    wlist.add(w);
  }
 
  private int [] colors = new int[]{color.blue,color.red,color.yellow,color.green};
  private class wave {
    //圆心
    int cx;
    int cy;
 
    //画笔
    paint p;
    //半径
    int r;
  }
}

myring.java

package com.example.mhy.shuibowen;
 
import android.content.context;
import android.graphics.canvas;
import android.graphics.color;
import android.graphics.paint;
import android.os.handler;
import android.os.message;
import android.util.attributeset;
import android.view.motionevent;
import android.view.view;
 
/**
 * created by mhy on 2016/6/16.
 */
public class myring extends view {
 
  /**
   * 圆心的x坐标
   */
  private float cx;
 
  /**
   * 圆心的y坐标
   */
  private float cy;
  /**
   * 圆环半径
   */
  private float radius = 0;
  /**
   * 默认画笔
   */
  private paint paint;
  private boolean isruning = false;
 
  public myring(context context, attributeset attrs) {
    super(context, attrs);
    initview();
  }
 
  private void initview() {
    radius = 0;
    paint = new paint();
    paint.setantialias(true);
    paint.setstyle(paint.style.stroke); // 空心圆
    paint.setstrokewidth(radius / 4); // 画笔宽度 半径4分之一
    paint.setcolor(color.green); // 画笔颜色
    paint.setalpha(255); //不透明
  }
 
  @override
  protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
    super.onmeasure(widthmeasurespec, heightmeasurespec);
  }
 
  @override
  protected void onlayout(boolean changed, int l, int t, int r, int b) {
    if(changed) {
      cx = getwidth() / 2;
      cy = getheight() / 2;
    }
  }
 
  @override
  protected void ondraw(canvas canvas) {
    canvas.drawcircle(cx, cy, radius, paint);
  }
 
  @override
  protected void onattachedtowindow() {
    super.onattachedtowindow();
  }
 
  @override
  protected void ondetachedfromwindow() {
    super.ondetachedfromwindow();
    isruning = false;
  }
 
  @override
  public boolean ontouchevent(motionevent event) {
    super.ontouchevent(event);
 
    if(event.getaction() == motionevent.action_down) {
      cx = event.getx();
      cy = event.gety();
      initview();
      startanim();
    }
    return true;
  }
 
  private handler handler = new handler(){
    @override
    public void handlemessage(message msg) {
 
      // 设置透明度
      int alpha = paint.getalpha();
      if(alpha == 0) {
        isruning = false;
      }
 
      // 透明度 慢慢变透明
      alpha = math.max(0, alpha-10);
 
      paint.setalpha(alpha);
 
      system.out.println(alpha);
 
      // 设置半径
      radius += 5;
      paint.setstrokewidth(radius / 3);
      invalidate();
 
      if(isruning) {
        handler.sendemptymessagedelayed(0, 50);
      }
    }
  };
  private void startanim() {
    isruning = true;
    handler.sendemptymessagedelayed(0, 50);
  }
 
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。