自定义圆角带边框ImageView

最近项目改版需要带阴影的圆角矩形，最后只实现了带边框的圆角矩形，阴影需要渐变，由于宝宝经验有限，只能参考被人的实现成了这样的。有路过的大神可以留下脚印，嘿嘿

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;

import com.trthi.mall.R;

/**
 * 圆角带边框矩形ImageView
 */
public class RectangleView extends ImageView {
private Paint paint;
private  Bitmap sbmp;
private float left;
private float top;
private float right;
private float bottom;

public RectangleView(Context context) {
this(context, null);

    }

public RectangleView(Context context, AttributeSet attrs) {
this(context, attrs,0);

    }

public RectangleView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
        paint = new Paint();
    }

protected void onDraw(Canvas canvas) {
int roundPx = 10;//圆角的大小，这个单位是像素
        paint.setAntiAlias(true);
        paint.setColor(getResources().getColor(R.color.text_color_0c66666)); //这里的颜色决定了边缘的颜色

        Drawable drawable = getDrawable();
if (drawable == null) {
return;
        }
if (getWidth() == 0 || getHeight() == 0) {
return;
        }

if(drawable instanceof BitmapDrawable){

            Bitmap b = ((BitmapDrawable) drawable).getBitmap();
            Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);
int w = getWidth();
int h = getHeight();
            RectF rectF = new RectF(0, 0, w, h);

            Bitmap roundBitmap = getCroppedBitmap(bitmap, w, h,roundPx);

            canvas.drawARGB(0, 0, 0, 0);
            canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
            canvas.drawBitmap(roundBitmap, 0, 0, null);
        }

    }

public Bitmap getCroppedBitmap(Bitmap bmp, int lengthx, int lengthy,int roundPx) {

if (bmp.getWidth() != lengthx || bmp.getHeight() != lengthy)
            sbmp = Bitmap.createScaledBitmap(bmp, lengthx, lengthy, false);
else
            sbmp = bmp;

        Bitmap output = Bitmap.createBitmap(sbmp.getWidth(), sbmp.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

final Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());
//left、right -:向右 +:向左 top、bottom -:向下 +:向上
final RectF rectF = new RectF(left,top,sbmp.getWidth()+right,sbmp.getHeight()+bottom);
// final RectF rectF = new RectF(-3, 0, sbmp.getWidth()+3, sbmp.getHeight() - 2);

final Paint paint = new Paint();
        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);

        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));

        canvas.drawBitmap(sbmp, rect, rect, paint);

return output;
    }

//这个方法是通过外部来控制边框的大小
public void setRectFSize(float left,float top,float right,float bottom){
this.left = left;
this.top = top;
this.right = right;
this.bottom = bottom;
    }

}

这里需要说明一点，给这个自定义的ImageView设置background是不起作用的，这个不也不知道为啥，所以就想到给他加一个父布局（带阴影的）来解决带阴影的圆角矩形。
我的建议，直接让设计给圆角带阴影的矩形最好，原因：一本身不用重写任何控件，减少了APP文件的大小；二节省了开发时间。但是最好还是要一起沟通和看具体需求了嘿嘿