flutter的生命周期对应iOS、Android

flutter生命周期 VS iOS和Android的生命周期方法对照表

AppLifecycleState	resumed	paused	inactive	detached
Android	onResume	onStop	onPause	onDetach
iOS FlutterViewController	viewDidAppear	viewDidDisappear	viewWillAppear	dealloc
同上			viewWillDisappear
iOS app life	applicationBecameActive	applicationDidEnterBackground	applicationWillEnterForeground	deaapplicationWillTerminatelloc
iOS Scene lifecycle	sceneBecameActive	appOrSceneDidEnterBackground	sceneWillEnterForeground	sceneWillDisconnect
同上	--	--	sceneWillResignActive	--

### 该方法 会先将当前的状态如果是resumed，取消；然后将当前页面的状态置为inactive
- (void)appOrSceneWillResignActive {
  [NSObject cancelPreviousPerformRequestsWithTarget:self
                                           selector:@selector(goToApplicationLifecycle:)
                                             object:@"AppLifecycleState.resumed"];
  [self goToApplicationLifecycle:@"AppLifecycleState.inactive"];
}

Android的状态对应

iOS的状态对应

参考

• Android的源码位置
• iOS涉及到的源码

在FlutterViewController
- (void)viewWillAppear:(BOOL)animated {
  TRACE_EVENT0("flutter", "viewWillAppear");
  if ([_engine.get() viewController] == self) {
    // Send platform settings to Flutter, e.g., platform brightness.
    [self onUserSettingsChanged:nil];

    // Only recreate surface on subsequent appearances when viewport metrics are known.
    // First time surface creation is done on viewDidLayoutSubviews.
    if (_viewportMetrics.physical_width) {
      [self surfaceUpdated:YES];
    }
    [[_engine.get() lifecycleChannel] sendMessage:@"AppLifecycleState.inactive"];
    [[_engine.get() restorationPlugin] markRestorationComplete];
  }

  [super viewWillAppear:animated];
}

- (void)viewDidAppear:(BOOL)animated {
  TRACE_EVENT0("flutter", "viewDidAppear");
  if ([_engine.get() viewController] == self) {
    [self onUserSettingsChanged:nil];
    [self onAccessibilityStatusChanged:nil];
    BOOL stateIsActive = YES;
#if APPLICATION_EXTENSION_API_ONLY
    if (@available(iOS 13.0, *)) {
      stateIsActive = self.flutterWindowSceneIfViewLoaded.activationState ==
                      UISceneActivationStateForegroundActive;
    }
#else
    stateIsActive = UIApplication.sharedApplication.applicationState == UIApplicationStateActive;
#endif
    if (stateIsActive) {
      [[_engine.get() lifecycleChannel] sendMessage:@"AppLifecycleState.resumed"];
    }
  }
  [super viewDidAppear:animated];
}

- (void)viewWillDisappear:(BOOL)animated {
  TRACE_EVENT0("flutter", "viewWillDisappear");
  if ([_engine.get() viewController] == self) {
    [[_engine.get() lifecycleChannel] sendMessage:@"AppLifecycleState.inactive"];
  }
  [super viewWillDisappear:animated];
}

- (void)viewDidDisappear:(BOOL)animated {
  TRACE_EVENT0("flutter", "viewDidDisappear");
  if ([_engine.get() viewController] == self) {
    [self invalidateKeyboardAnimationVSyncClient];
    [self ensureViewportMetricsIsCorrect];
    [self surfaceUpdated:NO];
    [[_engine.get() lifecycleChannel] sendMessage:@"AppLifecycleState.paused"];
    [self flushOngoingTouches];
    [_engine.get() notifyLowMemory];
  }

  [super viewDidDisappear:animated];
}

#pragma mark - Application lifecycle notifications

- (void)applicationBecameActive:(NSNotification*)notification {
  TRACE_EVENT0("flutter", "applicationBecameActive");
  [self appOrSceneBecameActive];
}

- (void)applicationWillResignActive:(NSNotification*)notification {
  TRACE_EVENT0("flutter", "applicationWillResignActive");
  [self appOrSceneWillResignActive];
}

- (void)applicationWillTerminate:(NSNotification*)notification {
  [self appOrSceneWillTerminate];
}

- (void)applicationDidEnterBackground:(NSNotification*)notification {
  TRACE_EVENT0("flutter", "applicationDidEnterBackground");
  [self appOrSceneDidEnterBackground];
}

- (void)applicationWillEnterForeground:(NSNotification*)notification {
  TRACE_EVENT0("flutter", "applicationWillEnterForeground");
  [self appOrSceneWillEnterForeground];
}

#pragma mark - Scene lifecycle notifications

- (void)sceneBecameActive:(NSNotification*)notification API_AVAILABLE(ios(13.0)) {
  TRACE_EVENT0("flutter", "sceneBecameActive");
  [self appOrSceneBecameActive];
}

- (void)sceneWillResignActive:(NSNotification*)notification API_AVAILABLE(ios(13.0)) {
  TRACE_EVENT0("flutter", "sceneWillResignActive");
  [self appOrSceneWillResignActive];
}

- (void)sceneWillDisconnect:(NSNotification*)notification API_AVAILABLE(ios(13.0)) {
  [self appOrSceneWillTerminate];
}

- (void)sceneDidEnterBackground:(NSNotification*)notification API_AVAILABLE(ios(13.0)) {
  TRACE_EVENT0("flutter", "sceneDidEnterBackground");
  [self appOrSceneDidEnterBackground];
}

- (void)sceneWillEnterForeground:(NSNotification*)notification API_AVAILABLE(ios(13.0)) {
  TRACE_EVENT0("flutter", "sceneWillEnterForeground");
  [self appOrSceneWillEnterForeground];
}


#pragma mark - Lifecycle shared

- (void)appOrSceneBecameActive {
  self.isKeyboardInOrTransitioningFromBackground = NO;
  if (_viewportMetrics.physical_width) {
    [self surfaceUpdated:YES];
  }
  [self performSelector:@selector(goToApplicationLifecycle:)             withObject:@"AppLifecycleState.resumed"             afterDelay:0.0f];
}

- (void)appOrSceneWillResignActive {
  [NSObject cancelPreviousPerformRequestsWithTarget:self                                           selector:@selector(goToApplicationLifecycle:)                                             object:@"AppLifecycleState.resumed"];
  [self goToApplicationLifecycle:@"AppLifecycleState.inactive"];
}

- (void)appOrSceneWillTerminate {
  [self goToApplicationLifecycle:@"AppLifecycleState.detached"];
  [self.engine destroyContext];
}

- (void)appOrSceneDidEnterBackground {
  self.isKeyboardInOrTransitioningFromBackground = YES;
  [self surfaceUpdated:NO];
  [self goToApplicationLifecycle:@"AppLifecycleState.paused"];
}

- (void)appOrSceneWillEnterForeground {
  [self goToApplicationLifecycle:@"AppLifecycleState.inactive"];
}

// Make this transition only while this current view controller is visible.
- (void)goToApplicationLifecycle:(nonnull NSString*)state {
  // Accessing self.view will create the view. Instead use viewIfLoaded
  // to check whether the view is attached to window.
  if (self.viewIfLoaded.window) {
    [[_engine.get() lifecycleChannel] sendMessage:state];
  }
}