捕获home按钮上的UIImagePickerController的解散事件

I've been working on an error in my program but I cannot seem to find a solution.

我一直在研究程序中的一个错误，但似乎找不到解决方案。

When the user opens the camera the UIImagePickerController is displayed and works great. Although when he presses the home button on the iPhone I want to remove an object from an NSMutableArray.

当用户打开相机时，UIImagePickerController就会显示出来，效果很好。虽然当他按下iPhone上的home键时，我想从NSMutableArray中删除一个对象。

For instance: The user opens the camera. An object is added to an NSMutableArray in another class. The user presses the home button The object should be removed.

例如:用户打开相机。对象被添加到另一个类的NSMutableArray中。用户按下home键，对象应该被删除。

I can't call the remove method when the application moves to the background because I need the other object to remain in the array for background location services.

当应用程序移动到后台时，我不能调用remove方法，因为我需要将另一个对象保留在后台位置服务的数组中。

Is there a way to catch the event when either pressing the home button or when the UIImagePicker closes itself by the home button event?

当按下home按钮或UIImagePicker被home按钮事件关闭时，是否有办法捕捉事件?

2 个解决方案

#1

You will have to post notication. For that in appDelegate method:

你必须张贴通知。对于appDelegate方法中的那个:

 - (void)applicationDidEnterBackground:(UIApplication *)application
 {
   [[NSNotificationCenter defaultCenter] postNotificationName:@"objectRemover" object:nil];
 }

Now were you open UIImagePickerController in your view controller and its viewDidLoad method

现在你在你的视图控制器和它的viewDidLoad方法中打开UIImagePickerController

-(void)viewDidLoad
{
 [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(removeObject) name:@"objectRemover" object:nil];
}

add selector method in your view controller were you will remove your object as it will be called when home button is pressed.

在你的视图控制器中添加选择器方法你将移除你的对象，当按下home按钮时它将被调用。

-(void)objectRemover
{
   // Your code remove object from array
}

#2

In ...AppDelegate.m class you will find following methods usefull

在……AppDelegate。你会发现以下方法是有用的

- (void)applicationWillResignActive:(UIApplication *)application {
- (void)applicationDidEnterBackground:(UIApplication *)application {
- (void)applicationWillTerminate:(UIApplication *)application {

#1