Question

我想在自定义ImageView周围添加黑色边框。目前我正在使用此类在ImageView中实现圆角顶角：

public class RoundedBitmapDisplayer implements BitmapDisplayer {

    private Context ctx;
    public RoundedBitmapDisplayer(Context context) {
        this.ctx = context;
    }
    @Override
    public Bitmap display(Bitmap bitmap, ImageView imageView) {
        Bitmap roundBitmap;
        try {

            roundBitmap = getRoundedCornerBitmap(ctx, bitmap, 10, bitmap.getWidth(), bitmap.getHeight(),
                      false, false, true, true);
        } catch (OutOfMemoryError e) {
            Log.e(ImageLoader.TAG, "Can't create bitmap with rounded corners. Not enough memory.", e);
            roundBitmap = bitmap;
        }
        imageView.setImageBitmap(roundBitmap);
        return roundBitmap;
    }

    /*
    private Bitmap getRoundedCornerBitmap(Bitmap bitmap) {
        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);

        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(0xFFFFFFFF);
        canvas.drawRoundRect(rectF, roundPixels, roundPixels, paint);

        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);

        return output;
    }*/
    public static Bitmap getRoundedCornerBitmap(Context context, Bitmap input, int pixels , int w , int h , boolean squareTL, boolean squareTR, boolean squareBL, boolean squareBR  ) {

        Bitmap output = Bitmap.createBitmap(w, h, Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        final float densityMultiplier = context.getResources().getDisplayMetrics().density;

        final int color = 0xff424242;
        final Paint paint = new Paint();

        final Rect rect = new Rect(0, 0, w, h);
        final RectF rectF = new RectF(rect);

        //make sure that our rounded corner is scaled appropriately
        final float roundPx = pixels*densityMultiplier;

        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);



        //draw rectangles over the corners we want to be square
        if (squareTL ){
            canvas.drawRect(0, 0, w/2, h/2, paint);

        }
        if (squareTR ){
            canvas.drawRect(w/2, 0, w, h/2, paint);

        }
        if (squareBL ){
            canvas.drawRect(0, h/2, w/2, h, paint);

        }
        if (squareBR ){
            canvas.drawRect(w/2, h/2, w, h, paint);

        }

        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));

        canvas.drawBitmap(input, 0,0, paint);
        return output;
    }   
}

Answer 1

您可以在画布中绘制线条。确保通过正确的坐标。在onDraw（）

    Paint bp= new Paint();
    bp.setColor(Color.RED);//set a color
    bp.setStrokeWidth(5);// set your stroke width
    // w and h are width and height of your imageview
    canvas.drawLine(0, 0, w, 0,bp);
    canvas.drawLine(0, 0, 0, h,bp);
    canvas.drawLine(w,h,w,0,bp);
    canvas.drawLine(w, h, 0,h , bp);

Answer 2

您可以设置包含<stroke />

的背景xml drawable

Answer 3

在drawable中创建image_border.xml文件

<gradient 
    android:angle="270">
</gradient>
<stroke 
    android:width="2dp" 
    android:color="#3b64a8" />
<corners 
    android:radius="2dp" />
<padding 
    android:left="1dp" 
    android:top="1dp" 
    android:right="1dp"
    android:bottom="1dp" />

并在imageview xml条目中使用此xml

<ImageView android:id="@+id/image"
    android:background="@drawable/image_border"   <!--add xml like this-->
    android:layout_height="wrap_content" 
    android:layout_width="wrap_content" 
    android:src="@drawable/image" />

在自定义imageview周围绘制边框

3 个答案: