Android 绘制一个Loading动画__向图片中缓慢填充颜色,从而形成动画效果

Android 绘制一个Loading动画__向图片中缓慢填充颜色,从而形成动画效果

需求：制作一个加载动画，向一个不规则图片图形中从从下到上依次填充颜色，形成动画效果。
效果如下：









代码如下：
LoadingAnimatorView.java

package cn.yw.lib.animation;

import cn.yw.lib.R;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class LoadingAnimatorView extends SurfaceView implements
SurfaceHolder.Callback, Runnable {
private SurfaceHolder holder;
private Bitmap bitmap;
private Paint paint1;
private Paint paint2;
public boolean flag = true;
private int y = 100;

public LoadingAnimatorView(Context context) {
super(context);
this.setFocusable(true);
this.setFocusableInTouchMode(true);
holder = this.getHolder();
holder.addCallback(this);
paint1 = new Paint();
paint1.setColor(Color.RED);
paint2 = new Paint();
paint2.setColor(Color.GRAY);
Bitmap bitmap1 = BitmapFactory.decodeStream(context.getResources()
.openRawResource(R.drawable.ic_launcher));
bitmap = bitmap1.extractAlpha();// 获取一个透明图片
y = bitmap.getWidth();//初始化y轴坐标
}
　　//改变裁剪区域
private void playAnimator() {
if (y > 0) {
y-=3;
}
}

private void drawLoadingAnimator() {
Canvas canvas = null;
try {
canvas = holder.lockCanvas();
if(canvas != null){
canvas.drawBitmap(bitmap, 100, 100,null);
canvas.drawColor(Color.GREEN);
canvas.drawBitmap(bitmap, 100, 100, paint2);
canvas.save();
　　　　　　　　　　//裁剪
canvas.clipRect(100, y+100, bitmap.getWidth()+100,
bitmap.getHeight()+100);
canvas.drawBitmap(bitmap, 100, 100, paint1);
canvas.restore();
}
/*
* Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
* Rect dst = new Rect(100, 100, bitmap.getWidth()+100, y+100);
* canvas.drawBitmap(bitmap, src, dst, paint2);
*/
} catch (Exception e) {
e.printStackTrace();
} finally {
try{
if (holder != null) {
holder.unlockCanvasAndPost(canvas);
}
}catch(Exception e){
e.printStackTrace();
}

}
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {

}

@Override
public void surfaceCreated(SurfaceHolder holder) {
new Thread(this).start();//开启绘制线程
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {

}
　　//绘制动画线程
@Override
public void run() {
while (flag) {
drawLoadingAnimator();
playAnimator();
try {
Thread.sleep(200);
} catch (Exception e) {
e.printStackTrace();
}
}
}

}

LoadingAnimatorActivity.java

package cn.yw.lib.animation;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;

@SuppressLint("NewApi")
public class LoadingAnimatorActivity extends Activity{
private LoadingAnimatorView view;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
view = new LoadingAnimatorView(this);
setContentView(view);
}
@Override
public void onBackPressed() {
view.flag = false;//结束绘制线程
super.onBackPressed();
}
}