android获取获取最上层的activity对象
时间: 2023-10-01 08:10:27 浏览: 42
可以通过 ActivityManager 和 UsageStatsManager 两种方式获取最上层的 Activity 对象。
使用 ActivityManager 获取:
```
ActivityManager activityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> runningTasks = activityManager.getRunningTasks(1);
ActivityManager.RunningTaskInfo runningTaskInfo = runningTasks.get(0);
ComponentName componentName = runningTaskInfo.topActivity;
Activity topActivity = null;
try {
topActivity = Class.forName(componentName.getClassName()).newInstance();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
}
```
使用 UsageStatsManager 获取:
```
UsageStatsManager usageStatsManager = (UsageStatsManager) getSystemService(Context.USAGE_STATS_SERVICE);
long endTime = System.currentTimeMillis();
long beginTime = endTime - 10000; // 获取最近10秒内的应用信息
List<UsageStats> usageStatsList = usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_BEST, beginTime, endTime);
if (usageStatsList != null && usageStatsList.size() > 0) {
UsageStats usageStats = usageStatsList.get(0);
String packageName = usageStats.getPackageName();
Activity topActivity = null;
try {
topActivity = Class.forName(usageStats.getTopActivity().getClassName()).newInstance();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
}
}
```
需要注意的是,使用 UsageStatsManager 需要用户授权。在 AndroidManifest.xml 中添加如下权限:
```
<uses-permission android:name="android.permission.PACKAGE_USAGE_STATS" tools:ignore="ProtectedPermissions"/>
```
并在应用启动时请求授权:
```
if (!checkUsageStatsPermission()) {
Intent intent = new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
```
其中 checkUsageStatsPermission 方法用于检查是否已经授权。