问题
I know this's a repeated question but i've looked all over the place and couldn't find a solution that works for me so...
I've an app that fetches movie data from TMDB API, it fetches it by page using a sync adapter, basically it runs great except when the sync adapter's periodic sync is ran while the app is open and the user is not at the first page, so my options were to force update the movies list and send the user to the top of the list which is totally bad experience so not considered as an option, Or i could check if the app is running, either in foreground or in the app stack that it's not visible to the user yet still running, so the best i could get to by searching was this piece of code:
public static boolean isAppRunning(final Context context, final String packageName) {
final ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
final List<ActivityManager.RunningAppProcessInfo> procInfos = activityManager.getRunningAppProcesses();
if (procInfos != null) {
for (final ActivityManager.RunningAppProcessInfo processInfo : procInfos) {
if (processInfo.processName.equals(packageName))
return true;
}
}
return false;
}
but for whatever reason it doesn't work correctly and sees the app as running even if i killed it by swiping, at first i thought it was because i have a sync adapter which could be considered as the app running so i used another process for it in the manifest using the
android:process=":service"
but it didn't work
Also thought about using variables in onStart and onStop of the activity but it's not guaranteed that onStop will be called when app is closed or killed so trying to avoid this method
this's my manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="inc.mourad.ahmed.watchme">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS" />
<uses-permission android:name="android.permission.READ_SYNC_SETTINGS" />
<uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS" />
<permission
android:name="inc.ahmed.mourad.ACCESS_WATCHME_DATABASE"
android:label="access my movies content provider"
android:protectionLevel="dangerous" />
<permission
android:name="inc.ahmed.mourad.ACCESS_WATCHME_SYNC_SERVICE"
android:label="access my sync service"
android:protectionLevel="dangerous" />
<permission
android:name="inc.ahmed.mourad.ACCESS_WATCHME_SYNC_AUTHENTICATOR_SERVICE"
android:label="access my sync authenticator dummy service"
android:protectionLevel="dangerous" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/Theme.AppCompat">
<activity android:name=".SplashScreenActivity"
android:theme="@style/Theme.AppCompat.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat">
<intent-filter>
<data
android:host="www.ahmedmourad.com"
android:pathPrefix="/watchme/"
android:scheme="http" />
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT"/>
<category android:name="android.intent.category.BROWSABLE"/>
</intent-filter>
</activity>
<activity
android:name=".SettingsActivity"
android:label="@string/title_activity_settings"
android:parentActivityName=".MainActivity">
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="inc.mourad.ahmed.watchme.MainActivity" />
</activity>
<activity android:name=".MovieDetailsActivity" />
<provider
android:name=".data.MovieProvider"
android:authorities="@string/content_authority"
android:enabled="true"
android:exported="false"
android:permission="inc.ahmed.mourad.ACCESS_WATCHME_DATABASE"
android:syncable="true" />
<!-- SyncAdapter's dummy authentication service -->
<service android:name=".sync.WatchMeAuthenticatorService"
android:permission="inc.ahmed.mourad.ACCESS_WATCHME_SYNC_AUTHENTICATOR_SERVICE"
android:process=":service">
<intent-filter>
<action android:name="android.accounts.AccountAuthenticator" />
</intent-filter>
<meta-data
android:name="android.accounts.AccountAuthenticator"
android:resource="@xml/authenticator" />
</service>
<!-- The SyncAdapter service -->
<service
android:name=".sync.WatchMeSyncService"
android:exported="true"
android:permission="inc.ahmed.mourad.ACCESS_WATCHME_SYNC_SERVICE"
android:process=":service">
<intent-filter>
<action android:name="android.content.SyncAdapter" />
</intent-filter>
<meta-data
android:name="android.content.SyncAdapter"
android:resource="@xml/syncadapter" />
</service>
</application>
so, any ideas? Thanks in advance
回答1:
We tweaked your idea and came up with this (in Kotlin, see below for Java):
fun appInForeground(context: Context): Boolean {
val activityManager = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
val runningAppProcesses = activityManager.runningAppProcesses ?: return false
return runningAppProcesses.any { it.processName == context.packageName && it.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND }
}
This is the equivalent in Java:
private boolean appInForeground(@NonNull Context context) {
ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> runningAppProcesses = activityManager.getRunningAppProcesses();
if (runningAppProcesses == null) {
return false;
}
for (ActivityManager.RunningAppProcessInfo runningAppProcess : runningAppProcesses) {
if (runningAppProcess.processName.equals(context.getPackageName()) &&
runningAppProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
return true;
}
}
return false;
}
Here's the relevant documentation.
回答2:
Original Answer : https://stackoverflow.com/a/48767617/10004454 The recommended way to do it in accordance with Android documentation is
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
}}
In your gradle (app) add : implementation "androidx.lifecycle:lifecycle-extensions:2.2.0"
Then to check the state at runtime call MyApplication().isActivityVisible()
来源：https://stackoverflow.com/questions/43378841/check-if-app-is-running-in-foreground-or-background-with-sync-adapter