/**         * Constant for {@link #importance}: this is a persistent process.         * Only used when reporting to process observers.         * @hide         */        public static final int IMPORTANCE_PERSISTENT = 50;            /**         * Constant for {@link #importance}: this process is running the         * foreground UI.         */        public static final int IMPORTANCE_FOREGROUND = 100;                /**         * Constant for {@link #importance}: this process is running something         * that is actively visible to the user, though not in the immediate         * foreground.         */        public static final int IMPORTANCE_VISIBLE = 200;                /**         * Constant for {@link #importance}: this process is running something         * that is considered to be actively perceptible to the user. An         * example would be an application performing background music playback.         */        public static final int IMPORTANCE_PERCEPTIBLE = 130;                /**         * Constant for {@link #importance}: this process is running an         * application that can not save its state, and thus can't be killed         * while in the background.         * @hide         */        public static final int IMPORTANCE_CANT_SAVE_STATE = 170;                /**         * Constant for {@link #importance}: this process is contains services         * that should remain running.         */        public static final int IMPORTANCE_SERVICE = 300;                /**         * Constant for {@link #importance}: this process process contains         * background code that is expendable.         */        public static final int IMPORTANCE_BACKGROUND = 400;                /**         * Constant for {@link #importance}: this process is empty of any         * actively running code.         */        public static final int IMPORTANCE_EMPTY = 500;  

<uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES"/> 

package com.example.demo;  import java.util.List;  import android.app.Activity; import android.app.ActivityManager; import android.app.ActivityManager.MemoryInfo; import android.app.ActivityManager.RunningAppProcessInfo; import android.content.Context; import android.content.pm.PackageManager; import android.content.pm.PackageManager.NameNotFoundException; import android.os.Bundle; import android.util.Log; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.Toast;  public class CleanProcessActivity extends Activity {    private static final String TAG = "Clean";    @Override   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_clean_process);   }   public void clean(View v){     //To change body of implemented methods use File | Settings | File Templates.      ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);      List<RunningAppProcessInfo> infoList = am.getRunningAppProcesses();      List<ActivityManager.RunningServiceInfo> serviceInfos = am.getRunningServices(100);       long beforeMem = getAvailMemory(this);      Log.d(TAG, "-----------before memory info : " + beforeMem);      int count = 0;      PackageManager pm = getPackageManager();          if (infoList != null) {        for (int i = 0; i < infoList.size(); ++i) {          RunningAppProcessInfo appProcessInfo = infoList.get(i);          Log.d(TAG, "process name : " + appProcessInfo.processName);          //importance 該進程的重要程度 分為幾個級別，數值越低就越重要。          Log.d(TAG, "importance : " + appProcessInfo.importance);                              // 一般數值大于RunningAppProcessInfo.IMPORTANCE_SERVICE的進程都長時間沒用或者空進程了          // 一般數值大于RunningAppProcessInfo.IMPORTANCE_VISIBLE的進程都是非可見進程，也就是在后臺運行著          if (appProcessInfo.importance > RunningAppProcessInfo.IMPORTANCE_VISIBLE) {            String[] pkgList = appProcessInfo.pkgList;            for (int j = 0; j < pkgList.length; ++j) {//pkgList 得到該進程下運行的包名              String appName = null;             try {               appName = (String) pm.getApplicationLabel(pm.getApplicationInfo(pkgList[j], 0));              } catch (NameNotFoundException e) {               // TODO Auto-generated catch block               e.printStackTrace();             }             Log.d(TAG, "It will be killed, package name : " + pkgList[j]+" -- "+appName );              am.killBackgroundProcesses(pkgList[j]);              count++;            }          }         }      }       long afterMem = getAvailMemory(this);      Log.d(TAG, "----------- after memory info : " + afterMem);      Toast.makeText(this, "clear " + count + " process, "            + (afterMem - beforeMem) + "M", Toast.LENGTH_LONG).show();    }   private long getAvailMemory(CleanProcessActivity cleanProcessActivity) {     // 獲取android當前可用內存大小      ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);      MemoryInfo mi = new MemoryInfo();      am.getMemoryInfo(mi);      //mi.availMem; 當前系統的可用內存      //return Formatter.formatFileSize(context, mi.availMem);// 將獲取的內存大小規格化      Log.d(TAG, "可用內存---->>>" + mi.availMem / (1024 * 1024));      return mi.availMem / (1024 * 1024);    }  }