这是我在应用程序中创建通知的方式：
public class NotificationService extends Service {
public static final String ACTION_FOREGROUND = "com.tfsapps.generic.FOREGROUND";
private static final String ACTION_BACKGROUND = "com.tfsapps.generic.BACKGROUND";
private static final String WIDGET_PLAY = "PLAY";
static final String WIDGET_PAUSE = "PAUSE";
private static final String WIDGET_NEXT = "NEXT";
private static final String WIDGET_BACK = "BACK";
private static final String CHANNEL_ID = "player_channel";
@SuppressWarnings("rawtypes")
private static final Class[] mStartForegroundSignature = new Class[]{int.class, Notification.class};
@SuppressWarnings("rawtypes")
private static final Class[] mStopForegroundSignature = new Class[]{boolean.class};
private NotificationManager mNM;
private Method mStartForeground;
private Method mStopForeground;
private Object[] mStartForegroundArgs = new Object[2];
private Object[] mStopForegroundArgs = new Object[1];
public static final int NOTIFICATION_ID = 3232;
/**
* This is a wrapper around the new startForeground method, using the older
* APIs if it is not available.
*/
void startForegroundCompat(int id, Notification notification) {
// If we have the new startForeground API, then use it.
if (mStartForeground != null) {
mStartForegroundArgs[0] = Integer.valueOf(id);
mStartForegroundArgs[1] = notification;
try {
mStartForeground.invoke(this, mStartForegroundArgs);
} catch (InvocationTargetException e) {
} catch (IllegalAccessException e) {
}
return;
}
callSetForeground(true);
mNM.notify(id, notification);
}
private void callSetForeground(boolean foreground) {
try {
Method method = getClass().getMethod("setForeground", boolean.class);
method.invoke(this, foreground);
} catch (NoSuchMethodException e) {
// Too bad!
} catch (IllegalArgumentException e) {
} catch (IllegalAccessException e) {
} catch (InvocationTargetException e) {
}
}
private void stopForegroundCompat(int id) {
if (mStopForeground != null) {
mStopForegroundArgs[0] = Boolean.TRUE;
try {
mStopForeground.invoke(this, mStopForegroundArgs);
} catch (InvocationTargetException e) {
} catch (IllegalAccessException e) {
}
return;
}
mNM.cancel(id);
callSetForeground(false);
}
@Override
public void onCreate() {
mNM = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
try {
mStartForeground = getClass().getMethod("startForeground", mStartForegroundSignature);
mStopForeground = getClass().getMethod("stopForeground", mStopForegroundSignature);
} catch (NoSuchMethodException e) {
mStartForeground = mStopForeground = null;
}
}
@Override
public void onDestroy() {
stopForegroundCompat(R.string.notification_service_started);
}
@Override
public void onStart(Intent intent, int startId) {
if (intent != null) {
handleCommand(intent);
}
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
try {
if (intent != null) {
handleCommand(intent);
return START_STICKY;
}
} catch (Exception e) {
Logger.e(e);
}
return START_STICKY_COMPATIBILITY;
}
@SuppressLint("NewApi")
private void handleCommand(Intent intent) {
if (ACTION_FOREGROUND.equals(intent.getAction())) {
final YouTubeFile ytf = PlayerDataManager.getInstance().getYouTubeFile();
String nowPlayingTitle = "";
if (ytf != null) {
nowPlayingTitle = ytf.getTitle();
}
String ns = Context.NOTIFICATION_SERVICE;
NotificationManager mNotificationManager = (NotificationManager) getSystemService(ns);
long when = System.currentTimeMillis();
final RemoteViews contentView = new RemoteViews(getPackageName(), R.layout.notification);
ReceiverNotification.s_RemoteView = contentView;
if (ytf != null) {
try {
Bitmap bmp = ImageLoader.getInstance().loadImageSync(ytf.getImageUrl());
contentView.setImageViewBitmap(R.id.icon_fav_notification, bmp);
} catch (Exception e) {
Logger.e(e);
}
}
contentView.setTextViewText(R.id.toptext, nowPlayingTitle);
Intent rewindIntent = new Intent(this, ReceiverNotification.class);
rewindIntent.putExtra("ACTION", 0);
rewindIntent.setAction("REWIND");
PendingIntent pendingIntent1 = PendingIntent.getBroadcast(getApplicationContext(), 000, rewindIntent,
FLAG_UPDATE_CURRENT);
contentView.setOnClickPendingIntent(R.id.imageButtonPlayLast, pendingIntent1);
Intent playIntent = new Intent(this, ReceiverNotification.class);
playIntent.putExtra("ACTION", 1);
playIntent.setAction("PLAY");
PendingIntent pendingIntent2 = PendingIntent
.getBroadcast(getApplicationContext(), 111, playIntent, FLAG_UPDATE_CURRENT);
contentView.setOnClickPendingIntent(R.id.imageButtonPlay, pendingIntent2);
Intent forwardIntent = new Intent(this, ReceiverNotification.class);
forwardIntent.putExtra("ACTION", 2);
forwardIntent.setAction("FORWARD");
PendingIntent pendingIntent3 = PendingIntent.getBroadcast(getApplicationContext(), 222, forwardIntent,
FLAG_UPDATE_CURRENT);
contentView.setOnClickPendingIntent(R.id.imageButtonPlayNext, pendingIntent3);
Intent exitIntent = new Intent(this, ReceiverNotification.class);
exitIntent.putExtra("ACTION", 3);
exitIntent.setAction("EXIT");
PendingIntent pendingIntent4 = PendingIntent
.getBroadcast(getApplicationContext(), 333, exitIntent, FLAG_UPDATE_CURRENT);
contentView.setOnClickPendingIntent(R.id.exit_icon, pendingIntent4);
contentView.setViewVisibility(R.id.exit_icon, View.VISIBLE);
if (PlayerManager.getInstance().isPlaying()) {
contentView.setImageViewResource(R.id.imageButtonPlay, R.drawable.ic_action_av_pause_light);
} else {
contentView.setImageViewResource(R.id.imageButtonPlay, R.drawable.ic_action_av_play_light);
}
Intent notificationIntent = new Intent(this, MainActivity.class);
PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
NotificationCompat.Builder builder = new NotificationCompat.Builder(GuiManager.getInstance().getMainActivity(), CHANNEL_ID);
builder.setContentIntent(contentIntent)
.setSmallIcon(R.drawable.ic_launcher)
.setWhen(when)
.setAutoCancel(false).setVibrate(new long[]{0L})
.setCustomContentView(contentView);
if (Build.VERSION.SDK_INT >= 21) {
builder.setVisibility(Notification.VISIBILITY_PUBLIC);
}
if(Build.VERSION.SDK_INT < Build.VERSION_CODES.O){
builder.setPriority(Notification.PRIORITY_DEFAULT);
} else {
createNotificationChannel();
}
Notification notification = builder.build();
notification.flags |= Notification.FLAG_NO_CLEAR;
notification.defaults |= Notification.DEFAULT_LIGHTS;
if (mNotificationManager != null) {
mNotificationManager.notify(NOTIFICATION_ID, notification);
}
startForeground(NOTIFICATION_ID, notification);
} else if (ACTION_BACKGROUND.equals(intent.getAction())) {
stopForegroundCompat(R.string.notification_service_started);
} else {
// sendWidgetCommand(intent);
}
}
private void createNotificationChannel() {
// Create the NotificationChannel, but only on API 26+ because
// the NotificationChannel class is new and not in the support library
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
CharSequence name = getString(R.string.notification_channel_title);
String description = getString(R.string.notification_channel_description);
int importance = NotificationManager.IMPORTANCE_DEFAULT;
NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
channel.setDescription(description);
// Register the channel with the system; you can't change the importance
// or other notification behaviors after this
NotificationManager notificationManager = getSystemService(NotificationManager.class);
if (notificationManager != null) {
notificationManager.createNotificationChannel(channel);
}
}
}
public static PendingIntent getPendingIntentonActivity(Context context, Class C) {
Intent intentleft = new Intent(context, C);
intentleft.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intentleft.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
return PendingIntent.getActivity(context, 1, intentleft, FLAG_UPDATE_CURRENT);
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
这就是我所说的代码：
void showAppNotification() {
Intent intent = new Intent(NotificationService.ACTION_FOREGROUND);
intent.setClass(mActivity, NotificationService.class);
ContextCompat.startForegroundService(mActivity, intent);
}
我有一个问题，在关闭应用程序后，通知消失并再次返回，知道是什么问题吗？
编辑
compileSdkVersion 28
minSdkVersion 16
targetSdkVersion 28
还有从Service