How to make an ImageView with rounded corners?

In Android, an ImageView is a rectangle by default. How can I make it a rounded rectangle (clip off all 4 corners of my Bitmap to be rounded rectangles) in the ImageView?

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This is pretty late in response, but for anyone else that is looking for this, you can do the following code to manually round the corners of your images.

http://www.ruibm.com/?p=184

This isn't my code, but I've used it and it's works wonderfully. I used it as a helper within an ImageHelper class and extended it just a bit to pass in the amount of feathering I need for a given image.

Final code looks like this:

package com.company.app.utils;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;

public class ImageHelper {
    public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int pixels) {
        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
                .getHeight(), Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);
        final float roundPx = pixels;

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

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

        return output;
    }
}

Hope this helps someone!

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While the above answer works, Romain Guy (a core Android developer) shows a better method in his blog which uses less memory by using a shader not creating a copy of the bitmap. The general gist of the functionality is here:

BitmapShader shader;
shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(shader);

RectF rect = new RectF(0.0f, 0.0f, width, height);

// rect contains the bounds of the shape
// radius is the radius in pixels of the rounded corners
// paint contains the shader that will texture the shape
canvas.drawRoundRect(rect, radius, radius, paint);

The advantages of this over other methods is that it:

does not create a separate copy of the bitmap, which uses a lot of memory with large images [vs most of the other answers here]

supports antialisasing [vs clipPath method]

supports alpha [vs xfermode+porterduff method]

supports hardware acceleration [vs clipPath method]

only draws once to the canvas [vs xfermode and clippath methods]

I've created a RoundedImageView based off this code that wraps this logic into an ImageView and adds proper ScaleType support and an optional rounded border.

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In the v21 of the Support library there is now a solution to this: it's called RoundedBitmapDrawable.

It's basically just like a normal Drawable except you give it a corner radius for the clipping with:

setCornerRadius(float cornerRadius)

So, starting with Bitmap src and a target ImageView , it would look something like this:

RoundedBitmapDrawable dr = RoundedBitmapDrawableFactory.create(res, src);
dr.setCornerRadius(cornerRadius);
imageView.setImageDrawable(dr);

链接地址: http://www.djcxy.com/p/5310.html

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