Android自定义View实现水波纹引导动画

一、实现效果图

关于贝塞尔曲线

二、实现代码

1.自定义view

package com.czhappy.showintroduce.view;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.View;
import android.widget.RelativeLayout;

/**
* Description: 水波纹动画引导view
* User: chenzheng
* Date: 2017/1/14 0014
* Time: 18:01
*/
public class RippleIntroView extends RelativeLayout implements Runnable {

private int mMaxRadius = 70;
private int mInterval = 20;
private int count = 0;

private Bitmap mCacheBitmap;
private Paint mRipplePaint;
private Paint mCirclePaint;
private Path mArcPath;

public RippleIntroView(Context context) {
 this(context, null);
}

public RippleIntroView(Context context, AttributeSet attrs) {
 this(context, attrs, 0);
}

public RippleIntroView(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 init();
}

private void init() {
 mRipplePaint = new Paint();
 mRipplePaint.setAntiAlias(true);
 mRipplePaint.setStyle(Paint.Style.STROKE);
 mRipplePaint.setColor(Color.WHITE);
 mRipplePaint.setStrokeWidth(2.f);

mCirclePaint = new Paint();
 mCirclePaint.setAntiAlias(true);
 mCirclePaint.setStyle(Paint.Style.FILL);
 mCirclePaint.setColor(Color.WHITE);

mArcPath = new Path();
}

/**
 * view大小变化时系统调用
 * @param w
 * @param h
 * @param oldw
 * @param oldh
 */
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
 super.onSizeChanged(w, h, oldw, oldh);
 if (mCacheBitmap != null) {
  mCacheBitmap.recycle();
  mCacheBitmap = null;
 }
}

@Override
protected void onDraw(Canvas canvas) {
 //获取加号图片view
 View mPlusChild = getChildAt(0);
 //获取提示图片view
 View mRefsChild = getChildAt(1);
 if (mPlusChild == null || mRefsChild == null) return;

//获取加号图片大小
 final int pw = mPlusChild.getWidth();
 final int ph = mPlusChild.getHeight();

//获取提示图片大小
 final int fw = mRefsChild.getWidth();
 final int fh = mRefsChild.getHeight();

if (pw == 0 || ph == 0) return;

//加号图片中心点坐标
 final float px = mPlusChild.getX() + pw / 2;
 final float py = mPlusChild.getY() + ph / 2;
 //提示图片左上角坐标
 final float fx = mRefsChild.getX();
 final float fy = mRefsChild.getY();

final int rw = pw / 2;
 final int rh = ph / 2;

if (mCacheBitmap == null) {
  mCacheBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
  Canvas cv = new Canvas(mCacheBitmap);
  super.onDraw(cv);

//清空所有已经画过的path至原始状态
  mArcPath.reset();

//起始轮廓点移至x，y坐标点,即加号图片正下方再往下20位置
  mArcPath.moveTo(px, py + rh + mInterval);
  //设置二次贝塞尔，实现平滑曲线，前两个参数为操作点坐标，后两个参数为结束点坐标
  mArcPath.quadTo(px, fy - mInterval, fx + fw * 0.618f, fy - mInterval);
  //0~255，数值越小越透明
  mRipplePaint.setAlpha(255);
  cv.drawPath(mArcPath, mRipplePaint);
  //绘制半径为6的实心圆点
  cv.drawCircle(px, py + rh + mInterval, 6, mCirclePaint);
 }

//绘制背景图片
 canvas.drawBitmap(mCacheBitmap, 0, 0, mCirclePaint);

//保存画布当前的状态
 int save = canvas.save();
 for (int step = count; step <= mMaxRadius; step += mInterval) {
  //step越大越靠外就越透明
  mRipplePaint.setAlpha(255 * (mMaxRadius - step) / mMaxRadius);
  canvas.drawCircle(px, py, (float) (rw + step), mRipplePaint);
 }
 //恢复Canvas的状态
 canvas.restoreToCount(save);
 //延迟80毫秒后开始运行
 postDelayed(this, 80);
}

@Override
public void run() {
 //把run对象的引用从队列里拿出来，这样，他就不会执行了，但 run 没有销毁
 removeCallbacks(this);
 count += 2;
 count ％= mInterval;
 invalidate();//重绘
}

/**
 * 销毁view时调用，收尾工作
 */
@Override
protected void onDetachedFromWindow() {
 super.onDetachedFromWindow();
 if (mCacheBitmap != null) {
  mCacheBitmap.recycle();
  mCacheBitmap = null;
 }
}
}

2.MainActivity.java

package com.czhappy.showintroduce.activity;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;

import com.czhappy.showintroduce.R;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

View view = findViewById(R.id.layout_ripple);
 view.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
   ((ViewGroup) v.getParent()).removeView(v);
  }
 });
}
}

3.activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:text="Hello World!" />

<com.czhappy.showintroduce.view.RippleIntroView
 android:id="@+id/layout_ripple"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:clickable="true"
 android:fitsSystemWindows="true"
 android:background="#AA000000">

<ImageView
  android:id="@+id/iv_plus"
  android:layout_marginTop="36dp"
  android:src="@mipmap/ic_add"
  android:layout_alignParentRight="true"
  android:layout_marginRight="6dp"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"/>

<ImageView
  android:src="@mipmap/tips_subscribe"
  android:id="@+id/tv_title"
  android:layout_below="@id/iv_plus"
  android:layout_marginTop="50dp"
  android:layout_alignParentRight="true"
  android:layout_marginRight="40dp"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"/>

</com.czhappy.showintroduce.view.RippleIntroView>

</FrameLayout>

三、源码下载

http://xiazai.jb51.net/201701/yuanma/AndroidShowIntroduce(jb51.net).rar