/**
    *
    *   add timmy 20161220
    *   clean memory thread
    */
     Runnable runnable = new Runnable() {

        @Override
        public void run() {
            if(mActivityManager==null){
                mActivityManager = (ActivityManager) mContext.getSystemService(Context.ACTIVITY_SERVICE);
            }
            List<ActivityManager.RunningAppProcessInfo> list = mActivityManager
                    .getRunningAppProcesses();
            if (list != null) {
                for (int i = 0; i < list.size(); i++) {
                    ActivityManager.RunningAppProcessInfo apinfo = list.get(i);
                    String[] pkgList = apinfo.pkgList;
                    if (apinfo.importance > ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
                      // 清理后台进程
                        for (int j = 0; j < pkgList.length; j++) {
                            String pkg = pkgList[j];
                            if(pkg.matches("com.android.*")){
                                Log.d(TAG,"not clean is system android pid pkg= " +pkg);
                            }else{
                                Log.d(TAG,"auto clean apk pkg= " + pkg);
                                mActivityManager.forceStopPackage(pkgList[j]);
                            }    
                        }
                    }
                }
            }
        }
    };