How to transmit data between viewcontrollers [iOS] And viewcontrollerios

How to transmit data between viewcontrollers [iOS] And viewcontrollerios

There are many ways to transmit data between viewcontrollers. The bloggers will summarize the two most commonly used methods for you:

We assume that there is View controller A and View controller B. In this case, View controller B is pushed by View controller A through the Navigation controller, that is to say, View Controller B is the subview controller of View Controller.

The following describes how to transmit data between view controllers through A-> B and B->.

1. View Controller A transmits data to View Controller B.

• Here, my view Controller A is ViewController View Controller B is CheckViewController. Connect View Controller A and View Controller B on the Storyboard, click link, and set segueidentifier in the property settings window. Here we set it to MainToCheck.
• Define attribute _ showArray in the CheckViewController. h file to receive data

@property (strong, nonatomic) NSArray *showArray;

• In the ViewController. m file, set-(void) prepareForSegue :( UIStoryboardSegue *) segue sender :( id) sender method:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{    if ([[segue identifier] isEqualToString:@"MainToCheck"]) {        CheckViewController *CheckVC = [segue destinationViewController];        CheckVC.showArray = [[NSArray alloc] initWithArray:_currentArray];    }}

This completes the data transmission of A-> B.

2. View Controller B transmits data to View Controller

Data cannot be transferred from the sub-View Controller to the parent View Controller Using the segue. The common practice is to use protocol as a listener. The specific method is as follows:

• Add the Protocol to CheckViewController. h (note that the added protocol is located between # import and # interface ):

@class LoadViewController;@protocol CheckViewDelegate <NSObject>-(void)LoadDataViewController:(CheckViewController *)controller didFinishLoadData:(NSMutableArray *)loadedArray;@end

• Add the attribute delegate as the listener in CheckViewController. h.

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

• Call this method in CheckViewController. m.

[self.delegate LoadDataViewController:self didFinishLoadData:testArray];

• Add the protocol to the ViewController. h file.

• Add listener settings when the CheckViewController instance is pushed out

CheckVC.delegate = self;

• Implement the method in step 3 in the ViewController. m file.

-(void)LoadDataViewController:(CheckViewController *)controller didFinishLoadData:(NSMutableArray *)loadedArray{    self.currentArray = loadedArray;}

In this way, data transmission between B-> A is completed. Relatively complex.