十月工作总结

1.  在surfaceView上用paint绘制 2012-10-30

         以下实现在camera预览界面上显示倒计时计数

//用到的变量

   //use to paint the count down time that delaying capture

   private Paint mDelayTimerPainter = new Paint();

   //use to clear the lastest paint of mDelayTimerPainter

   private Paint mDelayTimerUnPainter = new Paint();

   //the surface that use to paint by mDelayTimerPainter

   private SurfaceView mDelayTimerView;

   private DelayTimerOverlayHandler mDelayTimerOverlayHandler =

                                            newDelayTimerOverlayHandler();

  private int remainTime = 0;  

//创建surfaceView对象

         mDelayTimerView= (SurfaceView) findViewById(R.id.delay_timer_overlay);

//获取surfaceHolder

       SurfaceHolder delayTimerHolder = mDelayTimerView.getHolder();

//为delayTimerHolder添加mDelayTimerOverlayHandler的回调函数

//mDelayTimerOverlayHandler中重写SurfaceHolder.Callback的三个函数

       mDelayTimerOverlayHandler.setDelayTimerSurfaceHolder(delayTimerHolder);

       delayTimerHolder.addCallback(mDelayTimerOverlayHandler);

//将mDelayTimerView放在其他surfaceview的顶层显示

       mDelayTimerView.setZOrderMediaOverlay(true);

//先不显示该view

       mDelayTimerView.setVisibility(View.GONE);

//设置mDelayTimerPainter的颜色

       mDelayTimerPainter.setColor(getResources().getColor(R.color.delay_time_remain_text));

//设置mDelayTimerPainter画笔的粗细

       mDelayTimerPainter.setStrokeWidth(1);

//设置mDelayTimerPainter画笔的文字大小

       mDelayTimerPainter.setTextSize(24);

//这个用于绘制另一个paint，用于在每次更新倒计时前遮盖之前显示的文字

       mDelayTimerUnPainter.setColor(Color.TRANSPARENT);

// PorterDuff.Mode.CLEAR可以使得绘制在surfaceview上面的都清除

       mDelayTimerUnPainter.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));

       mDelayTimerUnPainter.setStrokeWidth(1);   

 

//继承自SurfaceHolder.Callback的mDelayTimerOverlayHandler

   class DelayTimerOverlayHandler implements SurfaceHolder.Callback {

       private SurfaceHolder mDelayTimerSurfaceHolder;

       public final String TAG = "DelayTimerOverlayHandler";

 

       @Override

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

           mDelayTimerSurfaceHolder = holder;

           mDelayTimerSurfaceHolder.setFormat(PixelFormat.TRANSPARENT);

        }

 

       @Override

       public void surfaceCreated(SurfaceHolder holder) {

           mDelayTimerSurfaceHolder = holder;

        }

 

       @Override

       public void surfaceDestroyed(SurfaceHolder holder) {

           mDelayTimerSurfaceHolder = null;

       }

 

       public SurfaceHolder getDelayTimerSurfaceHolder() {

           return mDelayTimerSurfaceHolder;

       }

 

       public void setDelayTimerSurfaceHolder(SurfaceHolder surfaceHolder) {

           mDelayTimerSurfaceHolder = surfaceHolder;

       }

}   

    public void onShutterButtonClick() {

//…

//按下拍照键后的处理

//将surfaceView弄为可见

     mDelayTimerView.setVisibility(View.VISIBLE);

//绘制

       mDelayTimerView.postInvalidate();

      remainTime = delayTime;

      mHandler.post(delayTimerRunnable); 

    }

   private Runnable delayTimerRunnable = new Runnable() {

                      publicvoid run() {

        if(remainTime> 0)

               {

                     String time =Integer.toString(remainTime);

                     String countDown =getString(R.string.pref_camera_delay_snap_count_down,time);

        //加锁canva

                     Canvas delayTimerCanvas =

                            mDelayTimerOverlayHandler.getDelayTimerSurfaceHolder().lockCanvas();

                                  if (delayTimerCanvas != null) {

        //清空之前绘制内容

                       delayTimerCanvas.drawRect(0,0,300,300, mDelayTimerUnPainter);

                                         mDelayTimerView.postInvalidate();

        //绘制倒计时计数

                                              delayTimerCanvas.drawText(countDown, 10,150, mDelayTimerPainter);

                         mDelayTimerOverlayHandler.getDelayTimerSurfaceHolder().unlockCanvasAndPost(delayTimerCanvas);

                          mDelayTimerView.postInvalidate();

                      }

                                     --remainTime;

                             mHandler.postDelayed(delayTimerRunnable, 1000);

               }

                         Else

//将view不显示

                                mDelayTimerView.setVisibility(View.GONE);

                      }

    };