BlurImageView.java

package exutech.com.agoratest;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.renderscript.Allocation;
import android.renderscript.Element;
import android.renderscript.RenderScript;
import android.renderscript.ScriptIntrinsicBlur;
import android.util.AttributeSet;
import android.widget.ImageView;

/**
 * Created by Elone on 16/7/6.
 */
public class BlurImageView extends ImageView {

    public BlurImageView(Context context) {
        super(context);
    }

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

    public BlurImageView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Drawable drawable = getDrawable();
	if (drawable == null) {
            super.onDraw(canvas);
            return;
        }
        Bitmap bitmap = drawableToBitmap(drawable);
        Bitmap blur = blur(getContext(), bitmap);
        setImageBitmap(blur);
        super.onDraw(canvas);
    }

    private Bitmap blur(Context context, Bitmap image) {
        int width = Math.round(image.getWidth() * 1.0f);
        int height = Math.round(image.getHeight() * 1.0f);
        Bitmap inputBitmap = Bitmap.createScaledBitmap(image, width, height, false);
        Bitmap outputBitmap = Bitmap.createBitmap(inputBitmap);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            RenderScript rs = RenderScript.create(context);
            ScriptIntrinsicBlur theIntrinsic = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
            Allocation tmpIn = Allocation.createFromBitmap(rs, inputBitmap);
            Allocation tmpOut = Allocation.createFromBitmap(rs, outputBitmap);
            theIntrinsic.setRadius(5.0f);
            theIntrinsic.setInput(tmpIn);
            theIntrinsic.forEach(tmpOut);
            tmpOut.copyTo(outputBitmap);
        }

        return outputBitmap;
    }

    private Bitmap drawableToBitmap(Drawable drawable) {
        Bitmap bitmap = null;

        if (drawable instanceof BitmapDrawable) {
            BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
            if (bitmapDrawable.getBitmap() != null) {
                return bitmapDrawable.getBitmap();
            }
        }

        if (drawable.getIntrinsicWidth() <= 0 || drawable.getIntrinsicHeight() <= 0) {
            bitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888); // Single color bitmap will be created of 1x1 pixel
        } else {
            bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
        }

        Canvas canvas = new Canvas(bitmap);
        drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
        drawable.draw(canvas);
        return bitmap;
    }

}