Android canvas的save()和restore()用法
2010-06-19 17:38:00 来源:WEB开发网在读Android SDK里面的samples里面游戏的时候,很多时候都看到对canvas的save()和restore()运用。
下面是个小程序,使用了这两个方面,使得旋转红色方块的时候,保证蓝色方块不受影响。
代码如下:
Java代码
package com.ray.test;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class Test extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new MyView(this));
}
class MyView extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder mHolder;
private Canvas canvas;
public MyView(Context context) {
super(context);
mHolder = getHolder();
mHolder.addCallback(this);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
canvas = mHolder.lockCanvas();
Paint mPaint = new Paint();
mPaint.setColor(Color.BLUE);
canvas.drawRect(100, 200, 200, 300, mPaint);
canvas.save();
canvas.rotate(45);
mPaint.setColor(Color.RED);
canvas.drawRect(150, 10, 200, 60, mPaint);
canvas.restore();
mHolder.unlockCanvasAndPost(canvas);
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
}
}
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