从presentModalViewController取回时如何更新滑块的值并进行切换? [英] How to update the value of slider and switch when get back from presentModalViewController?

问题描述

我有一些具有某些设置属性的帐户.作为设置，有 UISlider 的值和 UISwitch 的值.当我运行应用程序时，它可以正常工作，因为viewDidLoad方法有效，所以我可以显示 NSUserDefaults 中的最后一个值.顺便说一下，我的应用程序有一个标签栏控制器.因此，当我切换选项卡时，它也可以正常工作，因为我可以获取switch和slider的值并在viewWillAppear方法中更新它们.但是在我的设置开关中，我显示了一个其中包含用户列表的视图，因此用户可以选择任何帐户.从显示的视图返回时，我无法更新switch和Slider的值.我需要一个触发器方法来更新它们的值.有什么办法吗?

I have accounts which they have some settings attributes. As settings there are value of UISlider and value of UISwitch. When i run the application it works fine i can display the last value from NSUserDefaults because viewDidLoad method works. My application has a tab bar controller by the way. So when i switch tabs it works fine too because i can get the values of switch and slider and update them in viewWillAppear method. But in my setting switch, i present a view which there are user list in it, so the user can select any account. When i get back from presented view i can't update the values of switch and slider. I need a trigger method to update their values. Is there any way to do that?

推荐答案

是的，这是3种苹果方法:

Yes this are the 3 apple ways to do it:

1) Delegation
2) NSNotificationCenter
3) KVO

但是，对于您的特殊情况来说，模态视图是Apple推荐的一种委托模式，也是我推荐的一种.

However for your particular case a modal view, the delegation pattern is the one Apple recommends, and is the one I would recommend as well.

尽管如此，它需要比其他2个选项更多的编码.

It requires a bit more coding than the other 2 options though.

首先，您必须在模态显示的视图中声明协议:

First you have to declare the protocol in the view you are presenting modally:

in your .h

@protocol MyProtocol;

@interface MyClass : NSObject

@property (nonatomic, weak) id<MyProtocol> delegate;

@end

@protocol MyProtocol <NSObject>

-(void)updateValues:(NSArray *)values;

@end

然后在从原始视图控制器以模态形式呈现模态视图之前，只需像这样设置delgate

Then before presenting the modal view modally from the original view controller simply set the delgate like this

myModallyPresentedController.delegate = self;

然后让您的演示视图控制器采用该协议

Then have your presenting view controller adopt the protocol

in your .h

MyPresentingViewController : UIViewController <MyProtocol>

in .m

//Implement method:

-(void)updateValues:(NSArray *)values {
   //Update Values.
}

最后，当用户按下完成"时

Finally when user presses "Done"

您可以打电话

[delegate updatedValues:myValues];

并进行相应的更新.

希望有帮助.

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