我需要检查我的应用程序是在后台运行还是在前台运行，然后执行一些相对于它的操作。
我搜索了很多，没有明确的解决方案。
在其 onPause() 和 onResume() 方法中创建一个父活动，保留一些变量以相应地更新它们。当您创建任何新活动时，继承您的父活动。 虽然这是我觉得完成任务的最佳解决方案，但有时如果即使应用程序在后台单击电源按钮，也会调用它的 onResume()。
使用 GETTASKS 权限 - 这个解决方案也不错。但它只能用于调试目的。如果您想将您的应用放到 Google Play 商店中，则不需要。
还有其他首选的解决方案吗？
【问题讨论】：
标签： android android-activity background task foreground
这解决了我的问题：
private boolean isAppOnForeground(Context context,String appPackageName) {
ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
if (appProcesses == null) {
return false;
}
final String packageName = appPackageName;
for (ActivityManager.RunningAppProcessInfo appProcess : appProcesses) {
if (appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND && appProcess.processName.equals(packageName)) {
// Log.e("app",appPackageName);
return true;
}
}
return false;
}
【讨论】：
原答案：https://stackoverflow.com/a/60212452/10004454 根据 Android 文档推荐的方法是
class MyApplication : Application(), LifecycleObserver {
override fun onCreate() {
super.onCreate()
ProcessLifecycleOwner.get().lifecycle.addObserver(this);
}
fun isActivityVisible(): String {
return ProcessLifecycleOwner.get().lifecycle.currentState.name
}
@OnLifecycleEvent(Lifecycle.Event.ON_STOP)
fun onAppBackgrounded() {
//App in background
Log.e(TAG, "************* backgrounded")
Log.e(TAG, "************* ${isActivityVisible()}")
}
@OnLifecycleEvent(Lifecycle.Event.ON_START)
fun onAppForegrounded() {
Log.e(TAG, "************* foregrounded")
Log.e(TAG, "************* ${isActivityVisible()}")
// App in foreground
}}
在您的 gradle（应用程序）中添加：implementation "androidx.lifecycle:lifecycle-extensions:2.2.0"
然后在运行时检查状态调用MyApplication().isActivityVisible()
【讨论】：
使用AppVisibilityDetector，我实现了这个类来检测应用可见性状态。它可以检测前台和后台状态并执行回调方法。
AppVisibilityDetector.init(MyApp.this, new AppVisibilityCallback() {
@Override
public void onAppGotoForeground() {
//app is from background to foreground
}
@Override
public void onAppGotoBackground() {
//app is from foreground to background
}
});
MyApp 是您的应用程序类
public class MyApp extends Application { ... }
您不需要在 Activity 中添加一些其他代码或在 AndroidManifest.xml 中添加任何权限
【讨论】：
您可以使用流程生命周期所有者进行检查。
fun isAppOnForeground(): Boolean {
return ProcessLifecycleOwner.get().getLifecycle().getCurrentState()
.isAtLeast(Lifecycle.State.STARTED);
}
【讨论】：
您可以使用此代码获取您的应用的前台运行状态（true）
public boolean isAppForground(Context mContext) {
ActivityManager am = (ActivityManager) mContext.getSystemService(Context.ACTIVITY_SERVICE);
List<RunningTaskInfo> tasks = am.getRunningTasks(1);
if (!tasks.isEmpty()) {
ComponentName topActivity = tasks.get(0).topActivity;
if (!topActivity.getPackageName().equals(mContext.getPackageName())) {
return false;
}
}
return true;
}
【讨论】：
使用以下函数检查您的应用程序是在后台还是前台
public static Boolean getProcessState(Context mContext) {
ActivityManager am = (ActivityManager) mContext.getSystemService(Context.ACTIVITY_SERVICE);
boolean noProcessOnForeground = true;
boolean isProcessForeground = false;
System.out.println("Checking if process: " + mContext.getApplicationInfo().processName + " is Foreground or Background");
List<ActivityManager.RunningAppProcessInfo> current_processes = am.getRunningAppProcesses();
for (ActivityManager.RunningAppProcessInfo appProcess : current_processes) {
if (appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
noProcessOnForeground = false;
if ((mContext.getApplicationInfo().processName).equalsIgnoreCase(appProcess.processName)) {
isProcessForeground = true;
System.out.println("Process is Foreground");
break;
// Toast.makeText(getApplicationContext(), "Process is Foreground", Toast.LENGTH_SHORT).show();
} else {
System.out.println("Process is Background");
// Toast.makeText(getApplicationContext(), "Process is Background", Toast.LENGTH_SHORT).show();
isProcessForeground = false;
break;
}
}
}
if (noProcessOnForeground) {
System.out.println("there is no process on foreground so setting " + mContext.getApplicationInfo().processName + " as background");
isProcessForeground = false;
}
return isProcessForeground;
}
【讨论】：
只想在 Activity/Fragment 中使用以下代码：
final boolean isAlive = AppVisibilityHelper.isForeground(HomeActivity.this);
想制作一个像下面这样的类：
public class AppVisibilityHelper{
public static boolean isForeground(final Context context) {
final String packageName = "com.acb.android";
ActivityManager manager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningTaskInfo> runningTaskInfo = manager.getRunningTasks(1);
ComponentName componentInfo = runningTaskInfo.get(0).topActivity;
return componentInfo.getPackageName().equals(packageName);
}
}
如果您想每隔一秒检查一次，请在 Activity 中使用以下代码：
Runnable CheckAppIsRunning = new Runnable() {
@Override
public void run() {
final boolean isAlive = AppVisibilityHelper.isForeground(HomeActivity.this);
if (isAlive) {
// App is running
} else {
// App is not running
}
}
appIsRuningHandler.postDelayed(CheckAppIsRunning, 1000);
}
};
在 onCreate() 中只调用一次：
appIsRuningHandler.postDelayed(CheckAppIsRunning, 1000);
【讨论】：
检查应用处于前台状态还是后台状态
ActivityManager activityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
final String packageName = getPackageName();
for (ActivityManager.RunningAppProcessInfo appProcess : appProcesses)
{
if (appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_BACKGROUND && appProcess.processName.equals(packageName))
{
//if app in background state this will execute
Intent intent = getPackageManager().getLaunchIntentForPackage("hinditextonphoto.com.allcomponents");
startActivity(intent);
System.out.println("bbbbbbbbbbbbb background");
}
else if (appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND && appProcess.processName.equals(packageName))
{
//if app in forground state this will execute
System.out.println("bbbbbbbbbbbbb forground");
}
}
【讨论】：
BroadcastReceiver 或Service 时，当应用在后台时appProcess.importance 的值为300 或IMPORTANCE_SERVICE。
您可以使用ActivityManager.RunningAppProcessInfo 类查看应用状态。
public boolean isForegrounded() {
ActivityManager.RunningAppProcessInfo appProcessInfo = new ActivityManager.RunningAppProcessInfo();
ActivityManager.getMyMemoryState(appProcessInfo);
return (appProcessInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND ||
appProcessInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_VISIBLE);
}
【讨论】：