android圆角矩形进度条

最近做项目，有个一个需求，就是圆角进度条。效果图如下。









当时项目时间很紧，没多去想怎么实现最佳，就直接把美工给的圆角进度条裁剪成了四份。来做 Canvas 剪切绘制。这样虽然也能达到效果，但是服用性很差。最近网上搜索了很长时间，发现Paint画笔，有遮挡层的功能。android.graphics.Paint.setXfermode(Xfermode xfermode) 。其中一个参数就是

Mode.DST_OUT 显示底图与上层图非交集的底图图像。于是就有个思路，先绘制圆角矩形进度条，然后设置画笔遮挡属性，再绘制扇形，来遮罩圆角矩形。这样就可以实现圆角矩形进度条的功能了。

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.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback{

SurfaceHolder mSurfaceHolder;
boolean isRun;

/** 进度条背景**/
Bitmap bmpDes;
/** 移动角度**/
float m = 0;
/** 包围进度条背景的圆半径**/
float r;
/** 移动速度**/
float speed;

public MySurfaceView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
mSurfaceHolder = this.getHolder();
mSurfaceHolder.addCallback(this);
/** 加载进度条**/
bmpDes = BitmapFactory.decodeResource(getResources(), R.drawable.d1).copy(Bitmap.Config.ARGB_8888, true);
/** 计算半径**/
r = (float) Math.sqrt(Math.pow(bmpDes.getWidth()/2, 2) + Math.pow(bmpDes.getHeight()/2, 2));
/** 根据25s，计算移动速度**/
speed = (float) (360 / (25000 / 33.0));
}

@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
// TODO Auto-generated method stub

}

@Override
public void surfaceCreated(SurfaceHolder arg0) {
// TODO Auto-generated method stub
isRun = true;
new Thread(){
public void run(){
while(isRun){
long start = System.currentTimeMillis();
Canvas canvas = null;
synchronized (mSurfaceHolder) {
canvas = mSurfaceHolder.lockCanvas();
if(canvas != null ){
onGameDraw(canvas);
if(canvas != null && mSurfaceHolder != null){
mSurfaceHolder.unlockCanvasAndPost(canvas);
}
m += speed;
if(m >= 360)
m = 0;
}
}
long end = System.currentTimeMillis() - start;
if(end < 33){
try {
Thread.sleep(end);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}.start();
}

@Override
public void surfaceDestroyed(SurfaceHolder arg0) {
// TODO Auto-generated method stub
isRun = false;
}

private void onGameDraw(Canvas canvas){
/*		canvas.drawColor(Color.BLACK);
c = new Canvas(bmpDes);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setXfermode(new PorterDuffXfermode(Mode.DST_OUT));
int sc = c.saveLayer(0, 0, bmpDes.getWidth(), bmpDes.getHeight(), null, LAYER_FLAGS);
c.drawArc(new RectF(-(r - bmpDes.getWidth()/2), -(r - bmpDes.getHeight()/2), r*2, r*2), 0, m, true, paint);
c.restoreToCount(sc);
canvas.drawBitmap(bmpDes, 0, 0, null);*/

canvas.drawColor(Color.BLACK);
Paint paint = new Paint();
paint.setFilterBitmap(false);
// 绘制第二层
int sc = canvas.saveLayer(0, 0, 0 + bmpDes.getWidth(), 0 + bmpDes.getHeight(), null,
Canvas.MATRIX_SAVE_FLAG | Canvas.CLIP_SAVE_FLAG
| Canvas.HAS_ALPHA_LAYER_SAVE_FLAG
| Canvas.FULL_COLOR_LAYER_SAVE_FLAG
| Canvas.CLIP_TO_LAYER_SAVE_FLAG);
// 绘制进度条背景
canvas.drawBitmap(bmpDes, 0, 0, paint);
// 设置遮挡属性
paint.setXfermode(new PorterDuffXfermode(Mode.DST_OUT));
// 绘制遮挡扇形
canvas.drawArc(new RectF(-(r - bmpDes.getWidth()/2), -(r - bmpDes.getHeight()/2), r*2, r*2), 0, m, true, paint);
// 将第二层反馈给画布
canvas.restoreToCount(sc);
}
}

源码
http://download.csdn.net/detail/li_xiao_kang/8750631 点击打开链接