将旋转的 drawable 设置为 TextView 的 drawableLeft

Question

我想在 TextView 中旋转 drawableLeft。

我试过这段代码：

Drawable result = rotate(degree);
setCompoundDrawables(result, null, null, null);

private Drawable rotate(int degree)
{
    Bitmap iconBitmap = ((BitmapDrawable)originalDrawable).getBitmap();

    Matrix matrix = new Matrix();
    matrix.postRotate(degree);
    Bitmap targetBitmap = Bitmap.createBitmap(iconBitmap, 0, 0, iconBitmap.getWidth(), iconBitmap.getHeight(), matrix, true);

    return new BitmapDrawable(getResources(), targetBitmap);
}

但它在左侧可绘制对象的位置给我一个空白 space。

实际上，即使是最简单的代码也会给出空白 space:

Bitmap iconBitmap = ((BitmapDrawable)originalDrawable).getBitmap();
Drawable result = new BitmapDrawable(getResources(), iconBitmap);
setCompoundDrawables(result, null, null, null);

这个很好用：

 setCompoundDrawables(originalDrawable, null, null, null);

Answer 1

你不能只"cast"一个Drawable到一个BitmapDrawable

要将 Drawable 转换为 Bitmap，您必须 "draw" 它，如下所示：

Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap); 
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);

在此处查看 post：

How to convert a Drawable to a Bitmap?

Answer 2

根据the docs, if you want to set drawableLeft you should call setCompoundDrawablesWithIntrinsicBounds (int left, int top, int right, int bottom)。只有在 Drawable 上调用了 setBounds() 时，调用 setCompoundDrawables() 才有效，这可能就是您的 originalDrawable 有效的原因。

因此将您的代码更改为：

Drawable result = rotate(degree);
setCompoundDrawablesWithIntrinsicBounds(result, null, null, null);

将旋转的 drawable 设置为 TextView 的 drawableLeft

Set rotated drawable as TextView's drawableLeft

android

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