在android 4.3中恢复下溢

Question

我收到了IllegalStateException:还原异常中的下溢,这导致我的应用程序崩溃.这在Android 4.3更新后开始发生.在Android 3.0 - 4.2.x它工作正常.

例外情况发生在第二个

canvas.restore();

以下是我的绘图代码

private void doDraw(Canvas canvas) {
        if(mTickerBackGround!=null && (!mTickerBackGround.isRecycled())){
            canvas.drawBitmap(mTickerBackGround, 0, 0, null);
        }
        if((mBitMapBuffer!=null)){
            canvas.save();
            canvas.translate(mX, 0);
            if(!mBitMapBuffer.isRecycled()){
                canvas.drawBitmap(mBitMapBuffer, 0, 0, null);
            }
            canvas.restore();

            if(bitMapWidth+mX<mCanvasWidth){
                canvas.translate(bitMapWidth+mX, 0);    
                if(!mBitMapBuffer.isRecycled()){
                    canvas.drawBitmap(mBitMapBuffer, 0, 0, null);
                }
                canvas.restore();                   
            }

            if(bitMapWidth+mX<=0){
                mX = 0;
            }else if(Math.abs(mX)>(bitMapWidth)){                   
                mX= mCanvasWidth; 
            }

            mX-=TickerConstants.SCROLLING_SMOOTHNESS*density;;
        }
        if(mLogo!=null && (!mLogo.isRecycled())){
            canvas.drawBitmap(mLogo, mCanvasWidth-(60*density), mLogo.getHeight()/6, null);
        }
    }

我的问题是

1. 这个错误是什么意思？
2. 我该如何解决这个错误？

生成的堆栈跟踪消息是.第165行对应第二个canvas.restore()

08-13 18:13:09.083:E/AndroidRuntime(14139):FATAL EXCEPTION:Thread-506 08-13 18:13:09.083:E/AndroidRuntime(14139):java.lang.IllegalStateException:恢复08-13下溢18:13:09.083:E/AndroidRuntime(14139):在android.graphics.Canvas.restore(Native Method)08-13 18:13:09.083:E/AndroidRuntime(14139):at com.my.package.name. ticker.TickerSurfaceView $ TickerThread.doDraw(TickerSurfaceView.java:165)08-13 18:13:09.083:E/AndroidRuntime(14139):at com.my.package.name.ticker.TickerSurfaceView $ TickerThread.run(TickerSurfaceView.java :128)

Answer 1

错误发生在代码的这一部分:

    if(bitMapWidth+mX<mCanvasWidth){
        canvas.translate(bitMapWidth+mX, 0);    
        if(!mBitMapBuffer.isRecycled()){
            canvas.drawBitmap(mBitMapBuffer, 0, 0, null);
        }
        canvas.restore();                   
    }

你restore()没有save()先打电话就打电话.您甚至不需要调用它们translate(),您只需将x和y坐标传递给drawBitmap()调用即可.