ColorDrawable不能强转BitmapDrawable？？？

Question

谢谢你们点进来~

java.lang.ClassCastException: android.graphics.drawable.ColorDrawable cannot be cast to android.graphics.drawable.BitmapDrawable
 at com.jack.jianyu.widget.XCRoundImageView.onDraw(XCRoundImageView.java:50)

报错所在的代码

/**
 * 圆形的ImageView,可以直接当组件在布局中使用。
 */


public class XCRoundImageView extends ImageView {
    public XCRoundImageView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }

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

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

    @Override
    protected void onDraw(Canvas canvas) {

        Drawable drawable = getDrawable();

        if (drawable == null) {
            return;
        }

        if (getWidth() == 0 || getHeight() == 0) {
            return;
        }

        Bitmap b = ((BitmapDrawable) drawable).getBitmap();

        if (null == b) {
            return;
        }

        Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

        int w = getWidth(), h = getHeight();


        Bitmap roundBitmap = getCroppedBitmap(bitmap, w);
        canvas.drawBitmap(roundBitmap, 0, 0, null);

    }

    public static Bitmap getCroppedBitmap(Bitmap bmp, int radius) {
        Bitmap sbmp;
        if (bmp.getWidth() != radius || bmp.getHeight() != radius)
            sbmp = Bitmap.createScaledBitmap(bmp, radius, radius, false);
        else
            sbmp = bmp;
        Bitmap output = Bitmap.createBitmap(sbmp.getWidth(),
                sbmp.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final int color = 0xffa19774;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());

        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(Color.parseColor("#BAB399"));
        canvas.drawCircle(sbmp.getWidth() / 2 + 0.7f, sbmp.getHeight() / 2 + 0.7f,
                sbmp.getWidth() / 2 + 0.1f, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(sbmp, rect, rect, paint);


        return output;
    }
}

报错代码

Bitmap b = ((BitmapDrawable) drawable).getBitmap();

Answer 1

继承关系如上

直接继承同一父类,不能强转

可以借助Canvas将ColorDrawable转成Bitmap,用 BitmapDrawable的构造函数生成

public BitmapDrawable (Bitmap bitmap)

Answer 2

不能.

這都不是android問題, java不允許你cast一個object到不兼容的class

Answer 3

参考Java类对象类型转换知识，ColorDrawable 和 BitmapDrawable 是平级关系，无互相强制转换可能。类对象转换机制存在于具有父子关系的类对象之间，强制转换时，只能是父类对象强制转换成子类对象。