Android清理设备内存具体完整演示样例(一)

时间：2021-04-25 14:26:08

MainActivity例如以下:

package come.on;

import android.app.Activity;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

/**

 * Demo描写叙述:

 * 内存清理及内存工具类

 * 详细代码參见工具类MemoryUtils

 *

 */

public class MainActivity extends Activity {

	private Button mButton;

	private Context mContext;

	private EditText mEditText;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        init();

    }

    private void init(){

    	mContext=this;

    	Intent intent=new Intent("come.on.service");

    	//该Service无用,可去掉

    	startService(intent);

    	mEditText=(EditText) findViewById(R.id.editText);

    	mButton=(Button) findViewById(R.id.button);

    	mButton.setOnClickListener(new OnClickListener() {

			@Override

			public void onClick(View v) {

		        MemoryUtils.cleanMemory(mContext,mEditText);

			}

		});

    }

}

MemoryUtils例如以下:

package come.on;

import java.util.List;

import java.io.FileReader;

import android.os.Process;

import java.io.IOException;

import java.io.BufferedReader;

import android.widget.EditText;

import android.content.Context;

import java.io.InputStreamReader;

import android.app.ActivityManager;

import android.content.ComponentName;

import android.app.ActivityManager.MemoryInfo;

import android.app.ActivityManager.RunningTaskInfo;

import android.app.ActivityManager.RunningAppProcessInfo;

/**

 * 文档描写叙述:

 * 内存工具类

 *

 * 包含内容:

 * 1 内存清理即杀掉进程的几种方式

 * 2 获取内存总大小及其可用大小

 * 3 推断栈顶Activity名及其所属进程名

 *

 * 注意权限:

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

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

 *

 * 文档日期:

 * 2014年5月30日10:01:55

 *

 */

public class MemoryUtils {

	//----------> 下面为杀掉进程的几种方式

	public static void cleanMemory(Context context,EditText editText) {

		long beforeCleanMemory=getAvailMemory(context);

		System.out.println("---> 清理前可用内存大小:"+beforeCleanMemory+"M");

		ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

		RunningAppProcessInfo runningAppProcessInfo = null;

		List<RunningAppProcessInfo> runningAppProcessInfoList = activityManager.getRunningAppProcesses();

		for (int i = 0; i < runningAppProcessInfoList.size(); ++i) {

			runningAppProcessInfo = runningAppProcessInfoList.get(i);

			String processName = runningAppProcessInfo.processName;

			//调用杀掉进程的方法

			System.out.println("---> 開始清理:"+processName);

			killProcessByRestartPackage(context, processName);

		}

		long afterCleanMemory=getAvailMemory(context);

		System.out.println("---> 清理后可用内存大小:"+afterCleanMemory+"M");

		System.out.println("---> 节约内存大小:"+(afterCleanMemory-beforeCleanMemory)+"M");

		editText.setText("共清理:"+(afterCleanMemory-beforeCleanMemory)+"M");

	}

	//利用activityManager.restartPackage()方法杀死进程

	//该方法实际调用了activityManager.killBackgroundProcesses()方法

	public static void killProcessByRestartPackage(Context context,String packageName) {

		ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

		activityManager.restartPackage(packageName);

		System.gc();

	}

	//利用Process.killProcess(pid)杀死进程

	//注意事项:

	//1 该方式可自杀,即杀掉本进程

	//2 该方式可杀掉其它普通应用进程

	//3 该方式不可杀掉系统级应用即system/app应用

	public static void killProcessBykillProcess(int pid){

		Process.killProcess(pid);

	}

	//利用adb shell命令杀死进程

	public static void killProcessByAdbShell(int pid) {

		String cmd = "adb shell kill -9 " + pid;

		System.out.println("-------> cmd=" + cmd);

		try {

			java.lang.Process process = Runtime.getRuntime().exec(cmd);

			InputStreamReader inputStreamReader = new InputStreamReader(process.getInputStream());

			BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

			String line = null;

			while ((line = bufferedReader.readLine()) != null) {

				System.out.println("----> exec shell:" + line);

			}

			bufferedReader.close();

		} catch (IOException e) {

			e.printStackTrace();

		}

	}

	 //利用su进程的命令方式杀死进程

	 //1 得到su进程(super进程)

	 //  Runtime.getRuntime().exec("su");

	 //2 利用su进程运行命令

	 //  process.getOutputStream().write(cmd.getBytes());

	public static void killProcessBySu(int pid) {

		try {

			java.lang.Process process = Runtime.getRuntime().exec("su");

			String cmd = "kill -9 " + pid;

			System.out.println("-------> cmd = " + cmd);

			process.getOutputStream().write(cmd.getBytes());

			if ((process.waitFor() != 0)) {

				System.out.println("-------> su.waitFor()!= 0");

			} else {

				System.out.println("------->  su.waitFor()==0 ");

			}

		} catch (Exception e) {

			e.printStackTrace();

		}

	}

	//----------> 以上为杀掉进程的几种方式

	//获取当前进程名

	public static String getCurrentProcessName(Context context) {

		int pid = android.os.Process.myPid();

		ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

		for (RunningAppProcessInfo runningAppProcessInfo : activityManager.getRunningAppProcesses()) {

			if (runningAppProcessInfo.pid == pid) {

                String processName=runningAppProcessInfo.processName;

				return processName;

			}

		}

		return null;

	}

	//获取栈顶Activity名称

	public static String getTopActivityName(Context context) {

		String topActivityName = null;

		ActivityManager activityManager = (ActivityManager) (context.getSystemService(android.content.Context.ACTIVITY_SERVICE));

		List<RunningTaskInfo> runningTaskInfos = activityManager.getRunningTasks(1);

		if (runningTaskInfos != null) {

			ComponentName f = runningTaskInfos.get(0).topActivity;

			String topActivityClassName = f.getClassName();

			String temp[] = topActivityClassName.split("\\.");

			topActivityName = temp[temp.length - 1];

		}

		return topActivityName;

	}

	//获取栈顶Activity所属进程的名称

	public static String getTopActivityProcessName(Context context) {

		String processName = null;

		ActivityManager activityManager = (ActivityManager) (context.getSystemService(android.content.Context.ACTIVITY_SERVICE));

		List<RunningTaskInfo> runningTaskInfos = activityManager.getRunningTasks(1);

		if (runningTaskInfos != null) {

			ComponentName componentName = runningTaskInfos.get(0).topActivity;

			String topActivityClassName = componentName.getClassName();

			int index = topActivityClassName.lastIndexOf(".");

			processName = topActivityClassName.substring(0, index);

		}

		return processName;

	}

	//获取内存总大小

	public static long getTotalMemory() {

		// 系统的内存信息文件

		String filePath = "/proc/meminfo";

		String lineString;

		String[] stringArray;

		long totalMemory = 0;

		try {

			FileReader fileReader = new FileReader(filePath);

			BufferedReader bufferedReader = new BufferedReader(fileReader,1024 * 8);

			// 读取meminfo第一行,获取系统总内存大小

			lineString = bufferedReader.readLine();

			// 依照空格拆分

			stringArray = lineString.split("\\s+");

			// 获得系统总内存,单位KB

			totalMemory = Integer.valueOf(stringArray[1]).intValue();

			bufferedReader.close();

		} catch (IOException e) {

		}

		return totalMemory / 1024;

	}

	//获取可用内存大小

	public static long getAvailMemory(Context context) {

		ActivityManager activityManager=(ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);

		MemoryInfo memoryInfo = new MemoryInfo();

		activityManager.getMemoryInfo(memoryInfo);

		return memoryInfo.availMem / (1024 * 1024);

	}

}

ServiceSubclass例如以下:

package come.on;

import android.app.Service;

import android.content.Intent;

import android.os.IBinder;

public class ServiceSubclass extends Service {

	@Override

	public IBinder onBind(Intent intent) {

		return null;

	}

	@Override

	public void onCreate() {

		super.onCreate();

		System.out.println("---> Service的 onCreate()");

	}

	@Override

	public void onStart(Intent intent, int startId) {

		super.onStart(intent, startId);

		System.out.println("---> Service的 onStart()");

	}

}

main.xml例如以下:

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

   >

    <TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="測试内存清理"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="25dip"

        android:textSize="20sp"

     />

    <EditText

        android:id="@+id/editText"

        android:layout_width="160dip"

        android:layout_height="50dip"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="100dip"

        android:gravity="center"

        android:textSize="20sp"

        />

    <Button

        android:id="@+id/button"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="清理内存"

        android:layout_centerInParent="true"

         android:textSize="20sp"

        />

</RelativeLayout>

AndroidManifest.xml例如以下:

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="come.on"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="10" />

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

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

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

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

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

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

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

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

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

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

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

    <application

        android:icon="@drawable/a"

        android:label="@string/app_name" >

        <activity

            android:label="@string/app_name"

            android:name=".MainActivity" >

            <intent-filter >

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <service android:name=".ServiceSubclass">

            <intent-filter>

                <action android:name="come.on.service"/>

            </intent-filter>

        </service>

    </application>

</manifest>

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