package com.jackie.blurimage; 
 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.widget.ImageView; 
import android.widget.SeekBar; 
import android.widget.TextView; 
 
public class MainActivity extends AppCompatActivity { 
  private ImageView mBlurImage, mOriginImage; 
  private SeekBar mSeekBar; 
  private TextView mSeekProgress; 
 
  private int mAlpha; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
 
    initView(); 
    initData(); 
    initEvent(); 
  } 
 
  private void initView() { 
    mBlurImage = (ImageView) findViewById(R.id.blur_image); 
    mOriginImage = (ImageView) findViewById(R.id.origin_image); 
    mSeekBar = (SeekBar) findViewById(R.id.seek_bar); 
    mSeekProgress = (TextView) findViewById(R.id.seek_progress); 
  } 
 
  private void initData() { 
    // 获取图片 
    Bitmap originBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.blur); 
    Bitmap blurBitmap = BlurUtils.blur(this, originBitmap); 
 
    // 填充模糊后的图像和原图 
    mBlurImage.setImageBitmap(blurBitmap); 
    mOriginImage.setImageBitmap(originBitmap); 
  } 
 
  private void initEvent() { 
    mSeekBar.setMax(100); 
 
    mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { 
      @Override 
      public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { 
        mAlpha = progress; 
 
        mOriginImage.setAlpha((int) (255 - mAlpha * 2.55)); 
        mSeekProgress.setText(String.valueOf(mAlpha)); 
      } 
 
      @Override 
      public void onStartTrackingTouch(SeekBar seekBar) { 
 
      } 
 
      @Override 
      public void onStopTrackingTouch(SeekBar seekBar) { 
 
      } 
    }); 
  } 
} 

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 
  xmlns:android="http://schemas.android.com/apk/res/android" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  android:orientation="vertical"> 
 
  <FrameLayout 
    android:layout_width="match_parent" 
    android:layout_weight="1" 
    android:layout_height="0dp"> 
 
    <ImageView 
      android:id="@+id/blur_image" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:scaleType="centerCrop" 
      android:src="@drawable/blur"/> 
 
    <ImageView 
      android:id="@+id/origin_image" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:scaleType="centerCrop"/> 
  </FrameLayout> 
 
  <LinearLayout 
    android:layout_width="match_parent" 
    android:layout_height="80dp" 
    android:orientation="vertical"> 
 
    <SeekBar 
      android:id="@+id/seek_bar" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:layout_marginLeft="16dp" 
      android:layout_marginRight="16dp" 
      android:layout_marginTop="@dimen/activity_vertical_margin"/> 
 
    <TextView 
      android:id="@+id/seek_progress" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_gravity="center" 
      android:text="0" 
      android:textSize="24sp"/> 
  </LinearLayout> 
</LinearLayout> 

package com.jackie.blurimage; 
 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.renderscript.Allocation; 
import android.renderscript.Element; 
import android.renderscript.RenderScript; 
import android.renderscript.ScriptIntrinsicBlur; 
 
/** 
 * Created by Jackie on 2017/1/21. 
 * 高斯模糊工具类 
 */ 
 
public class BlurUtils { 
  /** 
   * 图片缩放比例 
   */ 
  private static final float SCALE_DEGREE = 0.4f; 
  /** 
   * 最大模糊度（在0.0到25.0之间） 
   */ 
  private static final float BLUR_RADIUS = 25f; 
 
  /** 
   * 模糊图片 
   * @param context  上下文 
   * @param bitmap  需要模糊的图片 
   * @return     模糊处理后的图片 
   */ 
  public static Bitmap blur(Context context,Bitmap bitmap) { 
    //计算图片缩小的长宽 
    int width = Math.round(bitmap.getWidth() * SCALE_DEGREE); 
    int height = Math.round(bitmap.getHeight() * SCALE_DEGREE); 
 
    //将缩小后的图片作为预渲染的图片 
    Bitmap inputBitmap = Bitmap.createScaledBitmap(bitmap, width, height, false); 
    //创建一张渲染后的输入图片 
    Bitmap outputBitmap = Bitmap.createBitmap(inputBitmap); 
 
    //创建RenderScript内核对象 
    RenderScript renderScript = RenderScript.create(context); 
    //创建一个模糊效果的RenderScript的工具对象 
    ScriptIntrinsicBlur scriptIntrinsicBlur = ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript)); 
 
    /** 
     * 由于RenderScript并没有使用VM来分配内存,所以需要使用Allocation类来创建和分配内存空间。 
     * 创建Allocation对象的时候其实内存是空的,需要使用copyTo()将数据填充进去。 
     */ 
    Allocation inputAllocation = Allocation.createFromBitmap(renderScript, inputBitmap); 
    Allocation outputAllocation = Allocation.createFromBitmap(renderScript, outputBitmap); 
 
    //设置渲染的模糊程度，25f是最大模糊度 
    scriptIntrinsicBlur.setRadius(BLUR_RADIUS); 
    //设置ScriptIntrinsicBlur对象的输入内存 
    scriptIntrinsicBlur.setInput(inputAllocation); 
    //将ScriptIntrinsicBlur输出数据保存到输出内存中 
    scriptIntrinsicBlur.forEach(outputAllocation); 
 
    //将数据填充到Allocation中 
    outputAllocation.copyTo(outputBitmap); 
 
    return outputBitmap; 
  } 
}