在画布上绘制对象/图像 [英] draw object/image on canvas

问题描述

是否有另一种在 android 中的画布上绘制对象的方法?

Is there another way to draw an object on a canvas in android?

draw() 中的这段代码不起作用:

This code inside draw() doesn't work:

Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.pushpin);

         canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null);  

实际上，它正在处理我的第一个代码，但是当我将它转移到另一个名为 MarkOverlay 的类时，它不再工作了.

Well actually, it's working on my 1st code but when I've transfered this to another class called MarkOverlay, it's not working anymore.

  markerOverlay = new MarkerOverlay(getApplicationContext(), p);
                      listOfOverlays.add(markerOverlay);  

我应该向 MarkerOverlay 传递什么参数才能使此代码工作?错误出现在 getResources() 中.

What parameter should I pass to MarkerOverlay to make this code work? The error is somewhere in getResources().

仅供参考，canvas.drawOval 工作正常，但我真的想绘制图像而不是椭圆形.:)

FYI, canvas.drawOval is perfectly working but I really want to draw an Image not an Oval. :)

推荐答案

我更喜欢这样做，因为它只生成一次图像:

I prefer to do this as it only generates the image once:

public class CustomView extends View {

    private Drawable mCustomImage;

    public CustomView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mCustomImage = context.getResources().getDrawable(R.drawable.my_image);
    }

    ...

    protected void onDraw(Canvas canvas) {
        Rect imageBounds = canvas.getClipBounds();  // Adjust this for where you want it

        mCustomImage.setBounds(imageBounds);
        mCustomImage.draw(canvas);
    }
}

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