android一键清理后台,Android 一键清理、内存清理功能实现

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360桌面、金山清理大师等都提供了一键清理、一键加速等功能，其实就是杀一些后台进程来达到释放内存的目的。

基本思路就是列出所有运行的进程，查看其重要值(RunningAppProcessInfo.importance，值越大说明进程重要程度越低)，可以设定一个阈值，如果该进程的重要值大于该阈值，就可以杀掉该进程。

进程的重要值有以下几个等级：

/**

* 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;

需要权限：

具体操作代码如下：

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 infoList = am.getRunningAppProcesses();

List 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 该进程的重要程度 分为几个级别，数值越低就越重要。

Log.d(TAG, "importance : " + appProcessInfo.importance);

// 一般数值大于RunningAppProcessInfo.IMPORTANCE_SERVICE的进程都长时间没用或者空进程了

// 一般数值大于RunningAppProcessInfo.IMPORTANCE_VISIBLE的进程都是非可见进程，也就是在后台运行着

if (appProcessInfo.importance > RunningAppProcessInfo.IMPORTANCE_VISIBLE) {

String[] pkgList = appProcessInfo.pkgList;

for (int j = 0; j < pkgList.length; ++j) {//pkgList 得到该进程下运行的包名

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) {

// 获取android当前可用内存大小

ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);

MemoryInfo mi = new MemoryInfo();

am.getMemoryInfo(mi);

//mi.availMem; 当前系统的可用内存

//return Formatter.formatFileSize(context, mi.availMem);// 将获取的内存大小规格化

Log.d(TAG, "可用内存---->>>" + mi.availMem / (1024 * 1024));

return mi.availMem / (1024 * 1024);

}

}

注意：

我这里选择阈值是IMPORTANCE_VISIBLE级别的，也就是非可见的后台进程和服务会被杀掉(一些系统进程肯定除外)。

清理的效果跟金山清理大师和360桌面的一键清理效果差不多。

如果不想杀的太凶，可以选择IMPORTANCE_SERVICE级别，杀掉那些长时间没用或者空进程了，这个级别的清理力度不够大，达不到金山清理大师的效果。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

本文标签： 一键后台内存功能android