Android API22环境下如何获取前后台所有运行应用的名称与PID

我明白你的问题啦——在Android 5.0（API21）之后，Google收紧了普通应用获取其他进程信息的权限，所以你用ActivityManager的旧方法只能拿到自己的应用进程。针对API22的情况，分两种场景给你解决方案：

普通应用无法直接获取其他应用的PID，但可以获取所有最近运行过的应用名称（包括前台后台），如果需要PID，只能拿到自己应用的。以下是实现代码：

步骤1：添加权限到Manifest #

首先在AndroidManifest.xml中添加权限：

<uses-permission android:name="android.permission.PACKAGE_USAGE_STATS"
    tools:ignore="ProtectedPermissions" />

步骤2：检查并引导用户授权 #

这个权限需要用户手动在系统设置中开启，所以先检查权限：

private boolean hasUsageStatsPermission(Context context) {
    AppOpsManager appOps = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
    int mode = appOps.checkOpNoThrow(AppOpsManager.OPSTR_GET_USAGE_STATS,
            android.os.Process.myUid(), context.getPackageName());
    return mode == AppOpsManager.MODE_ALLOWED;
}

private void requestUsageStatsPermission(Context context) {
    Intent intent = new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS);
    context.startActivity(intent);
}

步骤3：获取应用名称和可获取的PID #

// 先定义一个实体类存储应用信息
public class AppInfo {
    public String appName;
    public int pid;
    public String packageName;

    public AppInfo(String appName, int pid, String packageName) {
        this.appName = appName;
        this.pid = pid;
        this.packageName = packageName;
    }
}

public List<AppInfo> getRunningApps(Context context) {
    List<AppInfo> appInfoList = new ArrayList<>();
    PackageManager packageManager = context.getPackageManager();

    // 先获取自己应用的PID和信息
    ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    List<ActivityManager.RunningAppProcessInfo> ownProcesses = activityManager.getRunningAppProcesses();
    for (ActivityManager.RunningAppProcessInfo info : ownProcesses) {
        try {
            ApplicationInfo appInfo = packageManager.getApplicationInfo(info.processName, 0);
            String appName = packageManager.getApplicationLabel(appInfo).toString();
            appInfoList.add(new AppInfo(appName, info.pid, info.processName));
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
    }

    // 再通过UsageStatsManager获取其他应用的名称（无法获取PID）
    if (!hasUsageStatsPermission(context)) {
        return appInfoList;
    }

    UsageStatsManager usageStatsManager = (UsageStatsManager) context.getSystemService(Context.USAGE_STATS_SERVICE);
    long endTime = System.currentTimeMillis();
    long startTime = endTime - 1000 * 60 * 60; // 查询过去1小时内的应用

    List<UsageStats> usageStatsList = usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_BEST, startTime, endTime);
    if (usageStatsList == null || usageStatsList.isEmpty()) {
        return appInfoList;
    }

    // 去重并添加其他应用名称
    Set<String> addedPackages = new HashSet<>();
    for (AppInfo info : appInfoList) {
        addedPackages.add(info.packageName);
    }

    for (UsageStats stats : usageStatsList) {
        String packageName = stats.getPackageName();
        if (addedPackages.contains(packageName)) {
            continue;
        }
        try {
            ApplicationInfo appInfo = packageManager.getApplicationInfo(packageName, 0);
            String appName = packageManager.getApplicationLabel(appInfo).toString();
            appInfoList.add(new AppInfo(appName, -1, packageName)); // PID设为-1表示无法获取
            addedPackages.add(packageName);
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
    }

    return appInfoList;
}

如果你的应用是系统应用或者拥有android.permission.GET_TASKS权限，可以直接用ActivityManager.getRunningAppProcesses()获取所有应用的PID和名称：

public List<AppInfo> getAllRunningApps(Context context) {
    List<AppInfo> appInfoList = new ArrayList<>();
    ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    PackageManager packageManager = context.getPackageManager();

    List<ActivityManager.RunningAppProcessInfo> processInfos = activityManager.getRunningAppProcesses();
    for (ActivityManager.RunningAppProcessInfo info : processInfos) {
        try {
            ApplicationInfo appInfo = packageManager.getApplicationInfo(info.processName, 0);
            String appName = packageManager.getApplicationLabel(appInfo).toString();
            appInfoList.add(new AppInfo(appName, info.pid, info.processName));
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
    }

    return appInfoList;
}

记得在Manifest中添加权限：

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

补充说明：在API21+，Google对应用获取其他进程信息做了严格限制，主要是为了用户隐私和系统安全。普通应用只能通过UsageStatsManager获取应用名称，无法获取PID；只有系统应用或拥有特殊权限的应用才能获取完整的PID信息。

内容的提问来源于stack exchange，提问作者bukubapi