How to get the list of running applications?

I am working on an app which n开发者_开发知识库eeds the information of the apps running at the system up to now. Is there an API/method to retrieve that kind of information?

You cannot detect an App launch in Android, but you can get the list of currently open apps and check if the app you're looking for is open or not using the following code:

ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> runningAppProcessInfo = am.getRunningAppProcesses();

for (int i = 0; i < runningAppProcessInfo.size(); i++) {
  if(runningAppProcessInfo.get(i).processName.equals("com.the.app.you.are.looking.for")) {
    // Do your stuff here.
  }
}

You can also check if the app is running in the foreground using this method

public static boolean isForeground(Context ctx, String myPackage){
    ActivityManager manager = (ActivityManager) ctx.getSystemService(ACTIVITY_SERVICE);
    List< ActivityManager.RunningTaskInfo > runningTaskInfo = manager.getRunningTasks(1); 

    ComponentName componentInfo = runningTaskInfo.get(0).topActivity;
    if(componentInfo.getPackageName().equals(myPackage)) {
        return true;
    }       
    return false;
}

public static String getActiveApps(Context context) {

    PackageManager pm = context.getPackageManager();
    List<ApplicationInfo> packages = pm.getInstalledApplications(PackageManager.GET_META_DATA);

    String value = u.dateStamp(); // basic date stamp
    value += "---------------------------------\n";
    value += "Active Apps\n";
    value += "=================================\n";

    for (ApplicationInfo packageInfo : packages) {

        //system apps! get out
        if (!isSTOPPED(packageInfo) && !isSYSTEM(packageInfo)) {

            value += getApplicationLabel(context, packageInfo.packageName) + "\n" + packageInfo.packageName  + "\n-----------------------\n";

        }
    }

    return value;

    //result on my emulator

    /* 2 Ekim 2017 Pazartesi 14:35:17
    ---------------------------------
    Active Apps
    =================================
    SystemSetting
    com.xyz.systemsetting
    -----------------------
    myMail
    com.my.mail
    -----------------------
    X-plore
    com.lonelycatgames.Xplore
    -----------------------
    Renotify
    com.liamlang.renotify
    -----------------------
    Mail Box
    com.mailbox.email
    -----------------------   */


}

some opened apps

isSTOPPED

private static boolean isSTOPPED(ApplicationInfo pkgInfo) {

    return ((pkgInfo.flags & ApplicationInfo.FLAG_STOPPED) != 0);
}

isSYSTEM

private static boolean isSYSTEM(ApplicationInfo pkgInfo) {

    return ((pkgInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0);
}

getApplicationLabel

public static String getApplicationLabel(Context context, String packageName) {

    PackageManager        packageManager = context.getPackageManager();
    List<ApplicationInfo> packages       = packageManager.getInstalledApplications(PackageManager.GET_META_DATA);
    String                label          = null;

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

        ApplicationInfo temp = packages.get(i);

        if (temp.packageName.equals(packageName))
            label = packageManager.getApplicationLabel(temp).toString();
    }

    return label;
}

You can get information about running processes using the ActivityManager class.

MORE MODERN ANSWER (Nov 2022):

This can be handled by the new app usage api

The system collects the usage data on a per-app basis, aggregating the data over daily, weekly, monthly, and yearly intervals. The maximum duration that the system keeps this data is as follows:

Daily data: 7 days Weekly data: 4 weeks Monthly data: 6 months Yearly data: 2 years For each app, the system records the following data:

The last time the app was used

The total length of time the app was in the foreground for that time interval (by > day, week, month, or year)

Timestamp capturing when a component (identified by a package and activity name) ?> moved to the foreground or background during a day

Timestamp capturing when a device configuration changed (such as when the device orientation changed because of rotation)