android Bitmap圍繞一個點進行旋轉

在項目中需要使用定位功能，也就是一個點圍繞一個圓心進行旋轉，查看了canvas的函數也就只有一個 canvas.drawBitmap(bitmap, matrix, paint)通過使用Matrix來實現旋轉，這裡實現一個demo，功能就是小原點順時針繪制一個原然後逆時針撤銷這個圓，通過Timer來實現。代碼如下:   Surface.java這個是實現繪制圖形的類      

package com.example.test;  
  
import java.util.Timer;  
import java.util.TimerTask;  
  
import android.annotation.SuppressLint;  
import android.content.Context;  
import android.graphics.Bitmap;  
import android.graphics.BitmapFactory;  
import android.graphics.Canvas;  
import android.graphics.Color;  
import android.graphics.Matrix;  
import android.graphics.Paint;  
import android.graphics.PixelFormat;  
import android.graphics.PorterDuff.Mode;  
import android.os.Handler;  
import android.os.Message;  
import android.util.Log;  
import android.view.SurfaceHolder;  
import android.view.SurfaceView;  
import android.view.SurfaceHolder.Callback;  
  
@SuppressLint("HandlerLeak")  
class Surface extends SurfaceView implements Callback{  
  
    Bitmap bmp;  
    private Paint mPaint;  
    private SurfaceHolder mHolder;  
    public Surface(Context context) {  
        super(context);  
        mHolder = getHolder();  
        mHolder.addCallback(this);  
        mPaint = new Paint();  
        mPaint.setColor(Color.GREEN);  
        mPaint.setAntiAlias(true);//抗鋸齒   
        setFocusable(true);  
        setFocusableInTouchMode(true);  
//        setZOrderOnTop(true);   
//        mHolder.setFormat(PixelFormat.TRANSPARENT);//設置背景透明   
        bmp = BitmapFactory.decodeResource(getResources(), R.drawable.camera_r_local);  
        bmp = Bitmap.createScaledBitmap(bmp, 15, 15, false);  
    }  
  
    public Handler handler = new Handler(){  
        @Override  
        public void handleMessage(Message msg) {  
            switch (msg.what) {  
            case 0:  
                canvas_ok();  
                break;  
            }  
            super.handleMessage(msg);  
        }  
          
    };  
      
    public void canvas_ok(){  
         Canvas canvas = null;  
        try {  
            canvas = mHolder.lockCanvas();  
            canvas.drawColor(Color.TRANSPARENT, Mode.CLEAR);//清除屏幕   
//          canvas.save();   
            Matrix matrix = new Matrix();  
            matrix.postTranslate(130, 0);  
            matrix.postRotate(degree, 130 ,130);  
            canvas.drawBitmap(bmp, matrix, mPaint);  
//          canvas.restore();   
        } catch (Exception e) {  
        }finally {  
            if(canvas != null) {  
                mHolder.unlockCanvasAndPost(canvas);  
            }  
        }  
    }  
  
    int degree = 0;  
    Timer timer = new Timer();  
    boolean flag = true;  
    @Override  
    public void surfaceCreated(SurfaceHolder holder) {  
        canvas_ok();  
        timer.schedule(new TimerTask() {  
            @Override  
            public void run() {  
                if (flag) {  
                    degree++;  
                    if (degree == 360) {  
                        flag = false;  
                    }  
                }else {  
                    degree--;  
                    if(degree == -360 || degree == 0){  
                        flag = true;  
                    }  
                }  
                Log.e("flag", degree+"  : "+flag);  
                handler.sendEmptyMessage(0);  
            }  
        }, 50, 50);  
    }  
  
  
    @Override  
    public void surfaceChanged(SurfaceHolder holder, int format, int width,  
            int height) {  
          
    }  
  
  
    @Override  
    public void surfaceDestroyed(SurfaceHolder holder) {  
        if (timer != null) {  
            timer.cancel();  
            timer = null;  
        }  
    }  
}  

package com.example.test;

import java.util.Timer;
import java.util.TimerTask;

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff.Mode;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.SurfaceHolder.Callback;

@SuppressLint("HandlerLeak")
class Surface extends SurfaceView implements Callback{

Bitmap bmp;
private Paint mPaint;
private SurfaceHolder mHolder;
public Surface(Context context) {
super(context);
mHolder = getHolder();
mHolder.addCallback(this);
        mPaint = new Paint();
        mPaint.setColor(Color.GREEN);
        mPaint.setAntiAlias(true);//抗鋸齒
        setFocusable(true);
        setFocusableInTouchMode(true);
//        setZOrderOnTop(true);
//        mHolder.setFormat(PixelFormat.TRANSPARENT);//設置背景透明
bmp = BitmapFactory.decodeResource(getResources(), R.drawable.camera_r_local);
  bmp = Bitmap.createScaledBitmap(bmp, 15, 15, false);
}

public Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 0:
canvas_ok();
break;
}
super.handleMessage(msg);
}

};

public void canvas_ok(){
Canvas canvas = null;
try {
canvas = mHolder.lockCanvas();
canvas.drawColor(Color.TRANSPARENT, Mode.CLEAR);//清除屏幕
//         canvas.save();
       Matrix matrix = new Matrix();
       matrix.postTranslate(130, 0);
       matrix.postRotate(degree, 130 ,130);
       canvas.drawBitmap(bmp, matrix, mPaint);
//         canvas.restore();
} catch (Exception e) {
}finally {
            if(canvas != null) {
                mHolder.unlockCanvasAndPost(canvas);
            }
        }
}

int degree = 0;
Timer timer = new Timer();
boolean flag = true;
@Override
public void surfaceCreated(SurfaceHolder holder) {
canvas_ok();
timer.schedule(new TimerTask() {
@Override
public void run() {
if (flag) {
degree++;
if (degree == 360) {
flag = false;
}
}else {
degree--;
if(degree == -360 || degree == 0){
flag = true;
}
}
Log.e("flag", degree+"  : "+flag);
handler.sendEmptyMessage(0);
}
}, 50, 50);
}


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

}


@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (timer != null) {
timer.cancel();
timer = null;
}
}
}

 

    Main7.java是主類 

package com.example.test;  
  
import android.app.Activity;  
import android.os.Bundle;  
import android.widget.RelativeLayout;  
  
public class Main7 extends Activity{  
    Surface surface;  
    RelativeLayout.LayoutParams laParams;  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        surface = new Surface(this);  
        laParams = new RelativeLayout.LayoutParams(260,  260);  
        setContentView(surface, laParams);  
    }  
  
}  

package com.example.test;

import android.app.Activity;
import android.os.Bundle;
import android.widget.RelativeLayout;

public class Main7 extends Activity{
Surface surface;
RelativeLayout.LayoutParams laParams;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
surface = new Surface(this);
laParams = new RelativeLayout.LayoutParams(260,  260);
setContentView(surface, laParams);
}

}

 

  效果圖如下：