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();    }}