Android清理内存

Android内存清理，利用ActivityManager获取当前正在运行的进程，清理这些进程释放内存。

可以根据importance的不同来判断前台或后台RunningAppProcessInfo 里面的常量IMOPORTANCE就是上面所说的前台后台，其实IMOPORTANCE是表示这个app进程的重要性，因为系统回收时候，会根据IMOPORTANCE来回收进程的。具体可以去看文档。。

在配置文件中添加权限

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

内存清理代码以及获取系统内存和各个APP占用内存代码如下：

public class SystemInfoUtil {

/**

* 获取可用内存

*

* @param context

* @return

*/

public static long getAvailMemory(Context context) {

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

ActivityManager.MemoryInfo mi = new ActivityManager.MemoryInfo();

am.getMemoryInfo(mi);

return mi.availMem / (1024 * 1024);

}

/**

* 获取总内存

*

* @param context

* @return

*/

public static long getTotalMemory(Context context) {

String str1 = "/proc/meminfo";// 系统内存信息文件

String str2;

String[] arrayOfString;

long initial_memory = 0;

try {

FileReader localFileReader = new FileReader(str1);

BufferedReader localBufferedReader = new BufferedReader(

localFileReader, 8192);

str2 = localBufferedReader.readLine();// 读取meminfo第一行，系统总内存大小

arrayOfString = str2.split("\\s+");

initial_memory = Integer.valueOf(arrayOfString[1]).intValue() * 1024;// 获得系统总内存，单位是KB，乘以1024转换为Byte

localBufferedReader.close();

} catch (IOException e) {

}

return initial_memory / (1024 * 1024);

}

// public static final int IMPORTANCE_BACKGROUND = 400//后台

// public static final int IMPORTANCE_EMPTY = 500//空进程

// public static final int IMPORTANCE_SERVICE = 300//在服务中

// public static final int IMPORTANCE_VISIBLE = 200//在屏幕前端、获取不到焦点可理解为

// public static final int IMPORTANCE_FOREGROUND = 100//在屏幕最前端、可获取到焦点 可理解为Activity生命周期的OnResume();

/**

* 清理内存

*

* @param context

*/

public static void clearMemory(Context context) {

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

List<ActivityManager.RunningAppProcessInfo> list = activityManger.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_VISIBLE) {

for (int j = 0; j < pkgList.length; j++) {

/**清理不可用的内容空间**/

activityManger.killBackgroundProcesses(pkgList[j]);

}

}

}

}

}

/**

* 获取每个APP占用的内存

*

* @param context

*/

public static void getEveryAppMemory(Context context) {

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

List<ActivityManager.RunningAppProcessInfo> list = am.getRunningAppProcesses();

if (list != null) {

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

ActivityManager.RunningAppProcessInfo appinfo = list.get(i);

int[] myMempid = new int[]{appinfo.pid};

Debug.MemoryInfo[] appMem = am.getProcessMemoryInfo(myMempid);

int memSize = appMem[0].dalvikPrivateDirty / 1024;

Log.e("AppMemory", appinfo.processName + ":" + memSize);

}

}

}

/**

* 清理应用缓存

*

* @param context

*/

public static void clearAppCache(Context context) {

File[] dir = context.getCacheDir().listFiles();

if (dir != null) {

for (File f : dir) {

f.delete();

}

}

}

}