iOS design mode-delegate mode

A delegate is a behavior that gives an object an opportunity to react to a change in another object, or a corresponding other object. The basic idea is to solve the problem together.

In the program: in general

1. The tasks to be commissioned are:

1.1 Defining protocols and methods

1.2 Declaring a delegate variable

1.3 Setting up Proxies

1.4 Calling a delegate method from a delegate variable

2. The work that the agent needs to do is:

2.1 Following the agreement

2.2 Implementing a Delegate method

Here's a workaround for using delegates to implement page-pass values:

Join us There are two Viewcontroller, respectively: Viewcontroller and Trendviewcontroller

A. Requirements:

We want to implement a feature that jumps to Trendviewcontroller immediately when you click on a button on the Viewcontroller view and passes a string of strings past.

Two. Solution:

1. The most up-to-the-top declaration agreement in the ViewController.h file is as follows:

@protocol passtrendvaluedelegate-(void) Passtrendvalues: (NSString *) values; // 1.1 Defining protocols and methods @end

2. Continue declaring a delegate variable in ViewController.h

/// 1. Define a delegate variable to pass a value to a trend page ID <PassTrendValueDelegate> trenddelegate;

3. Enter the VIEWCONTROLLER.M file in the Click Button Event function , set the proxy

#pragma Mark click the Trend button-(void)    trendbtnclick{//Create the View    Trendviewcontroller *trendviewcontroller = [[Trendviewcontroller alloc] Initwithnibname:@ "  Trendviewcontroller"Bundle:nil"  ;    Self.trenddelegate// set Agent    [self.trenddelegate passtrendvalues:@ "ABC " ]; // page jump Save }

4. Enter TrendViewController.h, refer to Viewcontroller's header file, and add the proxy protocol as follows:

#import " ViewController.h " @interface Trendviewcontroller:uiviewcontroller<passtrendvaluedelegate>{}@end

5. Implement the Proxy function :

#pragma<span id= "0_nwp" style= "Width:auto; Height:auto; Float:none; " ><a id= "0_nwl" href= "http://cpro.baidu.com/cpro/ui/uijs.php?adclass=0&app_id=0&c=news&cf=1001&ch=0&di=128&fv= 18&is_app=0&jk=3d222ce8b1c3dc1c&k=mark&k0=mark&kdi0=0&luki=3&n=10&p=baidu& q=69003180_cpr&rb=0&rs=1&seller_id=1&sid=1cdcc3b1e82c223d&ssp2=1&stid=0&t= tpclicked3_hc&td=2116751&tu=u2116751&u=http%3a%2f%2fwww%2eandroiddev%2enet%2flvesli%5fdelegate%2f &urlid=0 "target=" _blank "mpid=" 0 "style=" text-decoration:none; " ><span style= "color: #0000ff; font-size:12px;width:auto;height:auto;float:none;" >mark</span></a></span> implementing the method of value-Transfer Protocol-(void) Passtrendvalues: (NSString *) values{NSLog (@"values:::%@", values);}

Run OK.

There are also ways to implement page pass values:

1. Notice

2. Methods

3. Proxy methods

4.SharedApplication

5.NSUserdefault

6. Pass through a single instance of class

iOS design mode-delegate mode