UI Basics--(5) Uiviewcontroller, intermediate pass value, forward value, reverse pass value

One, the middle pass value

Global variables

1. Store the median value (delegate--is more troublesome)

@property (Nonatomic,strong) NSString *labeltext;

2. Save the value (put in the Application object)

Yyappdelegate *appdelegate = [UIApplication sharedapplication].delegate;

Appdelegate.labeltext = Label.text;

3. Fetching data

Yyappdelegate *appdelegate = [UIApplication sharedapplication].delegate;

Label.text =appdelegate.labeltext;

Second, forward value

A->b

Local variables

1. Set a property in B to save the value LabelText

@property (Nonatomic,strong) NSString *labeltext;

2. Save value (before VA jumps to VB)

Yygreenviewcontroller *green = [[Yygreenviewcontroller alloc]init];

Green.labeltext = Label.text;

3. Fetch the data and set

Label.text =self.labeltext;

Third, the value of the reverse transmission

Protocol: Proxy (reverse pass value)

A <-b

1. Create the Protocol agent (. h), and declare the method (what to do, with the parameter value-is the value you want to pass),

2. Set the agent properties in B. h

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

and ————— stored value (. m) before the interface jumps

[Self.delegate method Name: What to save];

3.A (. h) Compliance Agreement

4. Obtain an agent in (. m),

Yygreenviewcontroller *b = [[Yygreenviewcontroller alloc]init];

B.delegate = self;

5. How to get the value to implement the Protocol (a)

UI Basics--(5) Uiviewcontroller, intermediate pass value, forward value, reverse pass value