使用圖像而不是繪圖指向特定位置（指南針）

Question

我正在使用此代碼，就像使用箭頭指向特定位置（使用GPS值）的指南針。 此代碼做得很好，除了我想用箭頭的圖像替換繪製箭頭..但我不知道如何。 請幫忙嗎？

@Override 
public void draw(Canvas canvas) { 
    double angle = calculateAngle(currentLongitude, currentLatitude, targetLongitude, targetLatitude); 
    //Correction; 
    angle-=90; 

    //Correction for azimuth 
    angle-=azimuth; 

    if((getContext() instanceof Activity) && ((Activity)getContext()).getWindowManager().getDefaultDisplay().getOrientation()==Configuration.ORIENTATION_PORTRAIT)angle-=90; 

    while(angle<0)angle=angle+360; 

    Rect rect = canvas.getClipBounds(); 

    int height = rect.bottom-rect.top; 
    int width = rect.right-rect.left; 
    int left = rect.left; 
    int top = rect.top; 

    if(height>width){ 
     top+=(height-width)/2; 
     height=width; 
    } 
    if(width>height){ 
     left+=(width-height)/2; 
     width=height; 
    } 

    float centerwidth = width/2f; 
    float centerheight = height/2f; 

    Paint p = new Paint(); 
    p.setColor(color); 
    p.setStyle(Paint.Style.FILL); 
    p.setAntiAlias(true); 

    float startX = left+(float)(centerwidth+Math.cos(deg2rad(angle))*width/3.0); 
    float startY = top+(float)(centerheight+Math.sin(deg2rad(angle))*height/3.0); 

    Path path = new Path(); 
    path.moveTo(
      startX, 
      startY); 
    path.lineTo(
      left+(float)(centerwidth+Math.cos(deg2rad(angle+140))*width/4.0), 
      top+(float)(centerheight+Math.sin(deg2rad(angle+140))*height/4.0)); 
    path.lineTo(
      left+(float)centerwidth, 
      top+(float)centerheight 
      ); 
    path.lineTo(
      left+(float)(centerwidth+Math.cos(deg2rad(angle+220))*width/4.0), 
      top+(float)(centerheight+Math.sin(deg2rad(angle+220))*height/4.0) 
      ); 

    path.lineTo(
      startX, 
      startY 
      ); 

    canvas.drawPath(path, p); 
} 

public DirectionImageView(Context context, AttributeSet attrs, int defStyle) { 
    super(context, attrs, defStyle); 
    init(); 
} 

public DirectionImageView(Context context, AttributeSet attrs){ 
    super(context,attrs); 
    init(); 
} 

public DirectionImageView(Context context){ 
    super(context); 
    init(); 
} 


public void onSensorChanged(SensorEvent event) { 
    azimuth = event.values[0]; 
    invalidate(); 
} 

public static double calculateAngle(double x1, double y1, double x2, 
     double y2) { 
    double dx = x2 - x1; 
    double dy = y2 - y1; 

    return (Math.atan2(dx, dy) * 180)/Math.PI; 

} 

public float getAzimuth() { 
    return azimuth; 
} 

public void setAzimuth(float azimuth) { 
    this.azimuth = azimuth; 
    invalidate(); 
} 

/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */ 
/* :: This function converts decimal degrees to radians : */ 
/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */ 
public static double deg2rad(double deg) { 
    return (deg * Math.PI/180.0); 
} 

/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */ 
/* :: This function converts radians to decimal degrees : */ 
/* ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: */ 
public static double rad2deg(double rad) { 
    return (rad * 180.0/Math.PI); 
} 

@Override 
protected void onAttachedToWindow() { 
    if(callback!=null)callback.onImageAttached(this); 
    super.onAttachedToWindow(); 
    Log.v(getClass().getName(),"onAttachedToWindow()"); 
} 

@Override 
protected void onDetachedFromWindow() { 
    if(callback!=null)callback.onImageDetached(this); 
    super.onDetachedFromWindow(); 
    Log.v(getClass().getName(),"onDetachedFromWindow()"); 
} 

public static abstract class AttachCallback { 
    public abstract void onImageAttached(DirectionImageView iv); 
    public abstract void onImageDetached(DirectionImageView iv); 
    public abstract void pauseAll(); 
    public abstract void resumeAll(); 
} 


public void setColor(int color){ 
    this.color = color; 
    invalidate(); 
} 

}

Answer 1

您可以使用BitmapFactory.decodeResource（）從您的\加載一個位圖資源\文件夾繪製（每個方向角？），然後使用canvas.drawBitmap（）來繪製它，如果你在每次迭代中加載一個新的，則接着是位圖的recycle（）（否則它會泄漏內存）。