在Android中的畫布上繪製圓圈外的位圖（箭頭）

Question

我剛剛開始在Android中創建一些自定義視圖，但我在繪製圓圈外的位圖（箭頭）時遇到問題。

這裏是我的代碼：

Canvas osCanvas = new Canvas(windowFrame); // Create a canvas to draw onto the new image 
    RectF outerRectangle = new RectF(0, 0, getWidth(), getHeight()); 
    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); // Anti alias allows for smooth corners 
    paint.setColor(Color.parseColor("#FAFAFA")); // This is the color of your activity background 
    osCanvas.drawRect(outerRectangle, paint); 
    final Paint stroke = new Paint(); 

    //paint.setColor(Color.TRANSPARENT); // An obvious color to help debugging 
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OUT)); // A out B http://en.wikipedia.org/wiki/File:Alpha_compositing.svg 
    float centerX = getWidth()/2; 
    float centerY = getHeight()/2; 
    double rad = Math.min(getWidth(), getHeight())/2.5 - menuInnerPadding; 
    float radius = (float) rad; 

    stroke.setColor(Color.parseColor("#999999")); 
    stroke.setStyle(Paint.Style.STROKE); 
    stroke.setAntiAlias(true); 
    stroke.setStrokeWidth(5f); 
    osCanvas.drawCircle(centerX , 
      centerY , radius - stroke.getStrokeWidth() +5f, stroke); 

    for(int i=0;i<elements.size();i++){ 
     double angle =0; 
     if(i==0){ 
      angle = startAngle; 
     }else{ 
      angle = startAngle+(i * ((2 * Math.PI)/elements.size())); 
     } 
     elements.get(i).x = (int) (centerX + Math.cos(angle)*(radius)); 
     elements.get(i).y = (int) (centerY + Math.sin(angle)*(radius)); 
     float ang = (float) Math.cos(angle)*(radius); 
     Path path = new Path(); 
     path.addCircle(elements.get(i).x,elements.get(i).y, radius, Path.Direction.CW); 
     if(BLINKER_ID == i){ 
      if(blinkerPain != null){ 
       osCanvas.drawBitmap(elements.get(i).bitmap,elements.get(i).x,elements.get(i).y,blinkerPain); 
       blinkerPain = null; 
      } 
     }else{ 

      // here i am drawing the red arrows (bitmap images) But it's not fitting outside the circle. 
      osCanvas.drawBitmap(elements.get(i).bitmap,elements.get(i).x ,elements.get(i).y ,textPaint); 
     } 


    } 

這裏是我的輸出

我認爲問題是與填充。

Answer 1

我沒有編寫新的寫入。 你應該檢查這個代碼。

@Override 
protected void onDraw(Canvas canvas) { 
    Paint paint = new Paint(); 
    paint.setColor(Color.BLUE); 
    paint.setStrokeWidth(2); 
    paint.setStyle(Paint.Style.STROKE); 
    canvas.drawColor(Color.WHITE); 

    float x = 400; 
    float y = 400; 
    float r = 200; 

    canvas.drawCircle(x , y , r , paint); 

    Bitmap icon = BitmapFactory.decodeResource(getContext().getResources(), R.mipmap.ic_launcher); 

    int length = 8; 

    float radian = (float)(Math.PI * 2f)/length; 

    for(int i = 0; i<length; i++) { 
     drawBitmap(canvas , icon , x , y , r, radian * i); 
    } 
} 

private void drawBitmap(Canvas canvas, Bitmap bitmap, float pivotX, float pivotY, float radius, float radian) { 
    Matrix m = new Matrix(); 
    m.postTranslate(-bitmap.getWidth()/2 , -bitmap.getHeight()/2); 
    m.postRotate((float)(radian * 180/Math.PI) + 90); 

    float drawHeight = radius + (bitmap.getHeight()/2); 

    m.postTranslate(((float)Math.cos(radian) * drawHeight) + pivotX 
      , ((float)Math.sin(radian) * drawHeight) + pivotY); 

    canvas.drawBitmap(bitmap , m , null); 
}