如何將畫布對象與屏幕中心對齊？

Question

我正在製作一個屏幕，我需要我的gBall在屏幕中心對齊。代碼如下： 代碼如下。

@Override 
    protected void onDraw(Canvas canvas) { 
    // TODO Auto-generated method stub 
    super.onDraw(canvas); 
    canvas.drawColor(Color.RED); 

    Paint textPaint = new Paint(); 
    textPaint.setColor(Color.BLUE); 
    textPaint.setTextAlign(Align.CENTER); 
    textPaint.setTextSize(canvas.getWidth()/7); 
    textPaint.setTypeface(font); 
    canvas.drawText("MY Text", (canvas.getWidth()/2), 
      (float) (canvas.getHeight() * 0.75), textPaint); 
    canvas.drawBitmap(gball, 0, (float) (canvas.getHeight() * .25), null);//This is where i need help 
} 

但我得到它對齊屏幕左側，任何人都可以幫忙嗎？

Answer 1

明白了這段代碼吧！

canvas.drawBitmap(gball, (canvas.getWidth()/2-(gball.getWidth()/2)), (float) (canvas.getHeight() * .25), null); 

Answer 2

您在屏幕的左側得到它，因爲你的X值設置爲0，它應該是

int startX= (canvas.getWidth()-gBall.getWidth())/2;//for horisontal position 
    int startY=(canvas.getHeight()-gBall.getHeight())/2;//for vertical position 
    canvas.drawBitmap(gball, startX, startY, null); 

另外，不要初始化的onDraw您paint（）方法。