Question

我是我的绘图应用程序，当我绘制路径时，它出现在黑色方块中，但不应该如此，请赐教。这是我的代码和屏幕截图：http://tinypic.com/r/2d9cuhl/8

 //setup drawing
private void setupDrawing(){
    drawPath = new Path();
    drawPaint = new Paint();
    drawPaint.setColor(paintColor);
    drawPaint.setAntiAlias(true);
    drawPaint.setStrokeWidth(20);
    drawPaint.setStyle(Paint.Style.STROKE);
    drawPaint.setStrokeJoin(Paint.Join.ROUND);
    drawPaint.setStrokeCap(Paint.Cap.ROUND);
    drawPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    canvasPaint = new Paint(Paint.DITHER_FLAG);
}

@Override
protected void onDraw(Canvas canvas) {
   canvas.drawBitmap(canvasBitmap, 0, 0, canvasPaint);
   canvas.drawPath(drawPath, drawPaint);
}

Answer 1

也许我没有被正确理解，但我找到了我的问题的答案，对于谁有这个问题：需要在清单中或仅在您绘制的视图中禁用硬件加速。 More Here

对于manifest.xml中的Activity： <activity android:hardwareAccelerated="false" />

仅限特定视图： view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);

Answer 2

这可能会对你有所帮助

LinearLayout mContent;
signature mSignature;
Button mClear, mGetSign, mCancel;
public int count = 1;
public String current = null;
private Bitmap mBitmap;
public Canvas  mCanvas;
View mView;
File mypath;

@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    this.requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.signature);


    mContent = (LinearLayout) findViewById(R.id.linearLayout);
    mSignature = new signature(this, null);
    mSignature.setBackgroundColor(Color.TRANSPARENT);

    mContent.addView(mSignature, LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
    mClear = (Button)findViewById(R.id.clear);
    mGetSign = (Button)findViewById(R.id.getsign);
    mGetSign.setEnabled(false);
    mCancel = (Button)findViewById(R.id.cancel);
    mView = mContent;


    mClear.setOnClickListener(new OnClickListener() 
    {        
        public void onClick(View v) 
        {
            Log.v("log_tag", "Panel Cleared");
            mSignature.clear();
            mGetSign.setEnabled(false);
        }
    });

    mGetSign.setOnClickListener(new OnClickListener() 
    {        
        public void onClick(View v) 
        {
            mSignature.save();
        }
    });

    mCancel.setOnClickListener(new OnClickListener() 
    {        
        public void onClick(View v) 
        {
            Log.v("log_tag", "Panel Canceled");
            Bundle b = new Bundle();
            b.putString("status", "cancel");
            Intent intent = new Intent();
            intent.putExtras(b);
            setResult(RESULT_OK,intent);  
            finish();
        }
    });

}

@Override
protected void onDestroy() {
    Log.w("GetSignature", "onDestory");
    super.onDestroy();
}

public class signature extends View 
{
    private static final float STROKE_WIDTH = 5f;
    private static final float HALF_STROKE_WIDTH = STROKE_WIDTH / 2;
    private Paint paint = new Paint();
    private Path path = new Path();
    private Paint mBitmapPaint = new Paint(Paint.DITHER_FLAG);

    private float lastTouchX;
    private float lastTouchY;
    private final RectF dirtyRect = new RectF();

    public signature(Context context, AttributeSet attrs) 
    {
        super(context, attrs);
        paint.setAntiAlias(true);
        paint.setColor(Color.WHITE);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeJoin(Paint.Join.ROUND);
        paint.setStrokeWidth(12);



    }
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        mCanvas = new Canvas(mBitmap);
    }

    public void save() 
    {

            mContent.draw(mCanvas); 
            ByteArrayOutputStream bs = new ByteArrayOutputStream();
            mBitmap.compress(Bitmap.CompressFormat.PNG, 50, bs);
            Intent intent = new Intent();
            intent.putExtra("byteArray", bs.toByteArray());
            setResult(1, intent);
            finish();
    }

    public void clear() 
    {
        path.reset();
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) 
    {
        canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
        canvas.drawPath(path, paint);


    }

    @Override
    public boolean onTouchEvent(MotionEvent event) 
    {
        float eventX = event.getX();
        float eventY = event.getY();
        mGetSign.setEnabled(true);

        switch (event.getAction()) 
        {
        case MotionEvent.ACTION_DOWN:
            path.moveTo(eventX, eventY);
            lastTouchX = eventX;
            lastTouchY = eventY;
            return true;

        case MotionEvent.ACTION_MOVE:

        case MotionEvent.ACTION_UP:

            resetDirtyRect(eventX, eventY);
            int historySize = event.getHistorySize();
            for (int i = 0; i < historySize; i++) 
            {
                float historicalX = event.getHistoricalX(i);
                float historicalY = event.getHistoricalY(i);
                expandDirtyRect(historicalX, historicalY);
                path.lineTo(historicalX, historicalY);
            }
            path.lineTo(eventX, eventY);
            break;

        default:
            debug("Ignored touch event: " + event.toString());
            return false;
        }

        invalidate((int) (dirtyRect.left - HALF_STROKE_WIDTH),
                (int) (dirtyRect.top - HALF_STROKE_WIDTH),
                (int) (dirtyRect.right + HALF_STROKE_WIDTH),
                (int) (dirtyRect.bottom + HALF_STROKE_WIDTH));

        lastTouchX = eventX;
        lastTouchY = eventY;

        return true;
    }

    private void debug(String string){
    }

    private void expandDirtyRect(float historicalX, float historicalY) 
    {
        if (historicalX < dirtyRect.left) 
        {
            dirtyRect.left = historicalX;
        } 
        else if (historicalX > dirtyRect.right) 
        {
            dirtyRect.right = historicalX;
        }

        if (historicalY < dirtyRect.top) 
        {
            dirtyRect.top = historicalY;
        } 
        else if (historicalY > dirtyRect.bottom) 
        {
            dirtyRect.bottom = historicalY;
        }
    }
    private void resetDirtyRect(float eventX, float eventY) 
    {
        dirtyRect.left = Math.min(lastTouchX, eventX);
        dirtyRect.right = Math.max(lastTouchX, eventX);
        dirtyRect.top = Math.min(lastTouchY, eventY);
        dirtyRect.bottom = Math.max(lastTouchY, eventY);
    }
}

}

Android油漆/绘制路径与透明背景

2 个答案: