android 开发工具类-毛玻璃，高斯模糊效果

先上代码吧

package com.sunofbeaches.himalayademo.utils;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.renderscript.Allocation;
import android.renderscript.Element;
import android.renderscript.RenderScript;
import android.renderscript.ScriptIntrinsicBlur;
import android.widget.ImageView;

public class ImageBlur {
    public static void makeBlur(ImageView imageview, Context context) {
        BitmapDrawable drawable = (BitmapDrawable) imageview.getDrawable();
        Bitmap bitmap = drawable.getBitmap();
        Bitmap blurred = blurRenderScript(bitmap, 10, context); //second parametre is radius max:25
        imageview.setImageBitmap(blurred); //radius decide blur amount
    }


    private static Bitmap blurRenderScript(Bitmap smallBitmap, int radius, Context context) {
        smallBitmap = RGB565toARGB888(smallBitmap);
        Bitmap bitmap = Bitmap.createBitmap(smallBitmap.getWidth(), smallBitmap.getHeight(), Bitmap.Config.ARGB_8888);
        RenderScript renderScript = RenderScript.create(context);
        Allocation blurInput = Allocation.createFromBitmap(renderScript, smallBitmap);
        Allocation blurOutput = Allocation.createFromBitmap(renderScript, bitmap);
        ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript));
        blur.setInput(blurInput);
        blur.setRadius(radius); // radius must be 0 < r <= 25
        blur.forEach(blurOutput);
        blurOutput.copyTo(bitmap);
        renderScript.destroy();
        return bitmap;

    }

    private static Bitmap RGB565toARGB888(Bitmap img) {
        int numPixels = img.getWidth() * img.getHeight();
        int[] pixels = new int[numPixels];

        //Get JPEG pixels.  Each int is the color values for one pixel.
        img.getPixels(pixels, 0, img.getWidth(), 0, 0, img.getWidth(), img.getHeight());

        //Create a Bitmap of the appropriate format.
        Bitmap result = Bitmap.createBitmap(img.getWidth(), img.getHeight(), Bitmap.Config.ARGB_8888);

        //Set RGB pixels.
        result.setPixels(pixels, 0, result.getWidth(), 0, 0, result.getWidth(), result.getHeight());
        return result;
    }
}

用法，特别简单

静态方法，直接调用

如果是本地图片设置好图片以后，把ImageView和上下文传过来

如果是网络图片，怎么使用呢？

如果是网络图片也是一样的，这里我举个例子。

但是要进行判空，判断有没有把图片设置好。

假设我使用的是

if (mBgCoverIv != null) {
            Picasso.with(this).load(album.getCoverUrlLarge()).into(mBgCoverIv, new Callback() {
                @Override
                public void onSuccess() {
                    Drawable drawable = mBgCoverIv.getDrawable();
                    if (drawable != null) {
                        ImageBlur.makeBlur(mBgCoverIv, XXXActivity.this);
                    }
                }

                @Override
                public void onError() {

                }
            });
        }

在喜马拉雅的实战项目中，会使用到这个工具类。