处理视频退到后台进前台没有继续播放

keyBoard/VC/KBPermissionViewController.m

@@ -45,6 +45,15 @@ static void *KBPermPlayerPresentationSizeContext = &KBPermPlayerPresentationSize
     [self.view addSubview:self.openButton];
     [self.view addSubview:self.helpLabel];
 
+    // 监听 App 前后台切换，保证从设置/后台回来后视频能继续播放
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(kb_appDidBecomeActive:)
+                                                 name:UIApplicationDidBecomeActiveNotification
+                                               object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(kb_appDidEnterBackground:)
+                                                 name:UIApplicationDidEnterBackgroundNotification
+                                               object:nil];
     
     [self.bgImageView mas_makeConstraints:^(MASConstraintMaker *make) {
         make.edges.equalTo(self.view);
@@ -128,6 +137,20 @@ static void *KBPermPlayerPresentationSizeContext = &KBPermPlayerPresentationSize
     self.kb_permPlayerLayer.frame = CGRectMake(0, 0, width, height);
 }
 
+#pragma mark - App Lifecycle
+
+- (void)kb_appDidBecomeActive:(NSNotification *)note {
+    // 仅在当前控制器可见时恢复播放
+    if (self.isViewLoaded && self.view.window && !self.view.hidden) {
+        [self kb_setupPermissionVideoPlayer];
+    }
+}
+
+- (void)kb_appDidEnterBackground:(NSNotification *)note {
+    // 进入后台时暂停，避免资源浪费
+    [self.kb_permPlayer pause];
+}
+
 - (void)dealloc {
     // 移除通知监听
     [[NSNotificationCenter defaultCenter] removeObserver:self];