iOS various value-transfer methods

The property pass value passes the information owned by the a page through the property to the B page using

The b page defines a Navititle property that, in a page, passes the value of the a page directly to the B page by assigning a value to the property.

#import <UIKit/UIKit.h>

#import "DetailViewController.h"

@interface rootviewcontroller:uiviewcontroller<changedelegate>

{

Uitextfield *TF;

}

@end

A ROOTVIEWCONTROLLER.M Page Implementation file

#import "RootViewController.h"

#import "DetailViewController.h"

@interface Rootviewcontroller ()

@end

@implementation Rootviewcontroller

Core code

-(void) Loadview

{

UIButton *btn = [UIButton buttonwithtype:uibuttontyperoundedrect];

Btn.frame = CGRectMake (0, 0, 100, 30);

[Btn settitle:@ "Push" forstate:0];

[Btn addtarget:self Action: @selector (pushaction:) forcontrolevents:uicontroleventtouchupinside];

[Self.view ADDSUBVIEW:BTN];

}

-(void) Pushaction: (ID) sender

{

TF = (Uitextfield *) [self.viewviewwithtag:1000];

Navigating the push to the next page

Pushviewcontroller into the stack reference count +1, and the control right to the system

Detailviewcontroller *detailviewcontroller = [[Detailviewcontrolleralloc]init];

attribute value, direct property assignment

Detailviewcontroller.navititle =tf.text;

Navigating the push to the next page

[Self.navigationControllerpushViewController:detailViewController Animated:yes];

[Detailviewcontrollerrelease];

}

b page DetailViewController.h file

#import <UIKit/UIKit.h>

@interface Detailviewcontroller:uiviewcontroller

{

Uitextfield *textfield;

NSString *_navititle;

}

@property (Nonatomic,retain) NSString *navititle;

@end

b page. m implementation file

#import "DetailViewController.h"

@interface Detailviewcontroller ()

@end

@implementation Detailviewcontroller

@synthesize Navititle =_navititle;

-(void) Loadview

{

Self.view = [[[Uiviewalloc]initwithframe:cgrectmake (0,0, 320,480)]autorelease];

Self.title = Self.navititle;

}

Proxy pass-through value

A page push to page B, if the information on page B wants to return (callback) to a page, using the proxy value, where B defines the protocol and the declaration agent, a to confirm and implement the agent, a as a proxy for B

A page RootViewController.h file

#import <UIKit/UIKit.h>

#import "DetailViewController.h"

@interface rootviewcontroller:uiviewcontroller<changedelegate>

{

Uitextfield *TF;

}

@end

A page ROOTVIEWCONTROLLER.M implementation file

#import "RootViewController.h"

#import "DetailViewController.h"

@interface Rootviewcontroller ()

@end

@implementation Rootviewcontroller

Core code

-(void) Loadview

{

UIButton *btn = [UIButton buttonwithtype:uibuttontyperoundedrect];

Btn.frame = CGRectMake (0, 0, 100, 30);

[Btn settitle:@ "Push" forstate:0];

A page push to page b

[Btn addtarget:self Action: @selector (pushaction:) forcontrolevents:uicontroleventtouchupinside];

[Self.view ADDSUBVIEW:BTN];

}

-(void) Pushaction: (ID) sender

{

TF = (Uitextfield *) [Self.view viewwithtag:1000];

Navigating the push to the next page

Pushviewcontroller into the stack reference count +1, and the control right to the system

Detailviewcontroller *detailviewcontroller = [[Detailviewcontroller alloc]init];

Proxy pass-through value

Detailviewcontroller.delegate =self;//to make himself an agent.

Navigating the push to the next page

[Self.navigationcontroller Pushviewcontroller:detailviewcontroller Animated:yes];

[Detailviewcontroller release];

}

Implementing Proxy methods

-(void) Changetitle: (NSString *) aStr

{

TF = (Uitextfield *) [Self.view viewwithtag:1000];

Tf.text = astr;//Assigns the parameters passed from page B to the TextField in page a

Tf.text = ASTR;

}

b page detailviewcontroller.m file

#import <UIKit/UIKit.h>

@interface Detailviewcontroller:uiviewcontroller

{

Uitextfield *textfield;

Defining proxies

id<changedelegate>_delegate;

}

@property (nonatomic,assign) id<changedelegate> delegate;

@end

Defining protocols

@protocol changedelegate <NSObject>

-(void) Changetitle: (NSString *) astr;//protocol method

@end

b page DetailViewController.h implementation file

#import "DetailViewController.h"

@interface Detailviewcontroller ()

@end

@implementation Detailviewcontroller

-(void) Loadview

{

Self.view = [[[UIView alloc]initwithframe:cgrectmake (0, 0, +, 480)]autorelease];

Uibarbuttonitem *doneitem = [[Uibarbuttonitemalloc]initwithbarbuttonsystemitem:uibarbuttonsystemitemdonetarget: Selfaction: @selector (doneaction:)];

Self.navigationItem.rightBarButtonItem = Doneitem;

[Doneitemrelease];

}

Pop back to a previous page

-(void) Doneaction: (ID) sender

{

if (self.delegate && [self.delegaterespondstoselector: @selector (changetitle:)])//If the agent exists and responds to changetitle this method

{

[Self.delegate ChangeTitle:textField.text];

[self.delegatechangetitle:textfield.text];//the Textfield.text parameter to the Changetitle method let the agent, that is, a page to implement this method

NSLog (@ "%@", self.navigationController.viewControllers);

[Self.navigationControllerpopViewControllerAnimated:YES];

}

}

Block

Several forms of block

No return value
void (^BLOCK1) (void);
Block1 = ^{
NSLog (@ "Bock demo");
};
Block1 ();

int return type
Int (^block2) (void);
Block2 = ^ (void)
{
int a = 1, b = 1;
int c = a+b;
return C;
};

There are parameters returned
Int (^BLOCK3) (int, int) = ^ (int a, int b)
{
int c = a +b;
return C;

};
NSLog (@ "bock=%d", BLOCK3);

Has a return value, has parameters and can modify the block of variables outside the block
static int sum = 10;//__blcik and static keyword or _block int sum = 10
Int (^BLOCK4) (int) =^ (int a)
{
sum=11;
int c = Sum+a; At this point, sum is modifiable, and if no static or _block keyword is added, the variables outside the block cannot be modified.
return C;
};
NSLog (@ "block4=%d", Block4 (4));

Block Pass Value

For example the value of a (ablock) page preacher B (bblock) page

In the A page ABlock.h

@interface ablock:uiviewcontroller<uitableviewdelegate,uitableviewdatasource>
{
UITableView *_tableview;
UILabel *labe;
Uiimageview *imagevies;
}
@end

-(void) TableView: (UITableView *) TableView Didselectrowatindexpath: (Nsindexpath *) Indexpath
{
[_tableview Deselectrowatindexpath:indexpath Animated:yes];

Bblcok *bblock = [[Bblcok alloc] Initwithblock:block_copy (^ (NSString *ablock) {
Labe.text = Ablock;
NSLog (@ "%@", Ablock);

})];


Bblock.imgeviews = Imagevies.image;
bblock. String = Labe.text;
[Self.navigationcontroller Pushviewcontroller:bblock Animated:yes];
[Bblock release];
}

In the A page Bblock.h

#import <UIKit/UIKit.h>
typedef void (^myblock) (NSString *);
@interface Bblcok:uiviewcontroller
{
Uiimageview *image;
Uitextfield *afield;
UIButton *abutt;
NSString *_string;
ID _imgeviews;
Myblock Myblock;
}
@property (nonatomic,copy) Myblock Myblock;
@property (nonatomic,retain) ID imgeviews;
@property (Nonatomic,retain) NSString *string;
-(ID) Initwithblock: (Myblock) Ablcok;
@end

//
Bblcok.m
Blcok
//
Created by Zhu on 13-8-12.
Copyright (c) 2013 Zhu Ji Fan. All rights reserved.
//

#import "Bblcok.h"

@interface Bblcok ()

@end

@implementation Bblcok
@synthesize imgeviews = _imgeviews, String = _string;
@synthesize myblock = _myblock;
-(ID) Initwithblock: (Myblock) Ablcok
{
if (self = [super init])
{
Self.myblock = Ablcok;
}
return self;
}

-(void) dealloc
{
[Super Dealloc];
}

-(void) Loadview
{
Uicontrol *cont = [[Uicontrol alloc] Initwithframe:cgrectmake (0, 0, 320, 568-44)];
[Cont addtarget:self action: @selector (Clcik) forcontrolevents:uicontroleventtouchupinside];
Self.view = cont;

afield = [[Uitextfield alloc] Initwithframe:cgrectmake (60, 10, 160, 30)];
Afield.borderstyle = Uitextborderstyleline;
Afield.placeholder = self. String;
[Self.view Addsubview:afield];

Abutt = [UIButton buttonwithtype:uibuttontyperoundedrect];
Abutt.frame = CGRectMake (60, 50, 70, 30);
[Abutt settitle:@ "Modify" forstate:0];
[Abutt addtarget:self Action: @selector (Abuttclcik:) forcontrolevents:uicontroleventtouchupinside];
[Self.view Addsubview:abutt];

Image = [[Uiimageview alloc] Initwithframe:cgrectmake (60, 100, 210, 260)];
Image.backgroundcolor = [Uicolor Bluecolor];
Image.image = Self.imgeviews;
[Self.view Addsubview:image];
[Image release];

}

-(Ibaction) Abuttclcik: (ID) sender
{
NSString *sting = Afield.text;
Myblock (Sting);
[Self.navigationcontroller Poptorootviewcontrolleranimated:yes];
}


-(void) Clcik
{
[Afield Resignfirstresponder];
}
-(void) viewdidload
{
[Super Viewdidload];
Do any additional setup after loading the view.
}

-(void) didreceivememorywarning
{
[Super didreceivememorywarning];
Dispose of any resources the can be recreated.
}

@end

iOS various value-transfer methods