文章目录
  1. 1. import "ViewControllerB.h"
  2. 2. import "ViewControllerA.h"

1.协议代理

A.h

\

#import <UIKit/UIKit.h>
@class ViewControllerA;

@protocol ViewControllerAdelegate
-(void)changeBgColorFromCtrlA:(ViewControllerA )aView withColor:(UIColor )color;
@end

@interface ViewControllerA : UIViewController
@property( assign, nonatomic ) id< ViewControllerAdelegate > delegate;

-(IBAction)changeColorAction:(id)sender;
@end

A.m

\

#import "ViewControllerA.h"

import "ViewControllerB.h"

@interface ViewControllerA ()

@end

@implementation ViewControllerA
@synthesize delegate;

//使用协议代理Delegate
-(IBAction)changeColorAction:(id)sender{
[delegate changeBgColorFromCtrlA:self withColor:[UIColor grayColor]];
[[self navigationController] popViewControllerAnimated:YES];
}

@end

最终实现在B

B.h

\

#import <UIKit/UIKit.h>

import "ViewControllerA.h"

@interface ViewControllerB : UIViewController<ViewControllerAdelegate>

@end

B.m

\

#import "ViewControllerB.h"

@implementation ViewControllerB

//响应协议代理Delegate
-(void)changeBgColorFromCtrlA:(ViewControllerA )aView withColor:(UIColor )color{
[self.view setBackgroundColor:color];
}
@end

2.通知中心(其他同上面的例子)

a.m

\

//通知中心NSNotificationCenter
-(IBAction)changeColorAction2:(id)sender{
UIColor *color = [UIColor greenColor];
[[NSNotificationCenter defaultCenter] postNotificationName:@"ChangeColorKey" object:color];
[[self navigationController] popViewControllerAnimated:YES];
}

b.m

\

#import "ViewControllerB.h"

@implementation ViewControllerB

  • (void)viewDidLoad
    {
    [super viewDidLoad];
    //注册
    [[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(changeColor:)
                                               name:@&quot;ChangeColorKey&quot;
                                             object:nil];
    
    }

//响应通知中心NSNotificationCenter

  • (void)changeColor:(NSNotification *)notification{
    if([notification object] != nil)
    {
      UIColor *color = [notification object];
      [self.view setBackgroundColor:color];
    
    }
    }
    @end

3.NSString

NSString *string = @"abc";

比较:[a  isEqualToString:b]

匹配开头结尾: [a hasPrefix:@"ab"] ;        [a hasSuffix:@".txt"];

忽略大小写比较: [a caseInsensitiveCompare:b] == NSOrderedSame;

拼接: NSString *newS = [NSString stringWithFormat:@"%@%@",a,b ];        //已有的话用[a  appendFormat :[NSString stringWithFormaat:@"hhhhhhh"]    ];

分割:(字符串分割)

\

NSString *string = [[NSString alloc] initWithString:@"One,Two,Three,Four"];
NSArray *array = [string componentsSeparatedByString:@","];

(数组组成字符串)\

//从数组合并元素到字符串- componentsJoinedByString:
NSArray *array = [[NSArray alloc] initWithObjects:@"One",@"Two",@"Three",@"Four",nil];
NSString *string = [array componentsJoinedByString:@","];

大写: [a uppercaseString];

小写: [a lowercaseString]

截取:

从头开始:[a substringToIndex:3];

到哪里: [a substringFromIndex:3];

一段: [a substringWithRange:NSMakeRange(0,4)];

文件扩展名: [path pathExtension]

\

/—————-从文件读取字符串:initWithContentsOfFile方法—————-/  

NSString *path = @"astring.text";
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@"astring:%@",astring);
[astring release];

/—————-写字符串到文件:writeToFile方法—————-/

NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
NSLog(@"astring:%@",astring);
NSString *path = @"astring.text";
[astring writeToFile: path atomically: YES];
[astring release];

4.NSSArray

\

NSArray *array = [[NSArray alloc] initWithObjects:@"One",@"Two",@"Three",@"Four",nil];  //注意用nil结尾

增加元素: addObject

删除:removeObjectAtIndex:1 

复制数组:

直接复制

\

NSMutableArray *MutableArray = [[NSMutableArray alloc] init];
NSArray *array = [NSArray arrayWithObjects:
@"a",@"b",@"c",nil];
MutableArray = [NSMutableArray arrayWithArray:array];
用循环:

\

NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];
for(int i = 0; i < [oldArray count]; i++)
{
obj = [[oldArray objectAtIndex:i] copy];
[newArray addObject: obj];
}
快速枚举:

\

for(id obj in oldArray)
{
[newArray addObject: obj];
}

或者:

\

NSEnumerator *enumerator;
enumerator = [oldArray objectEnumerator]; //reverseObjectEnumerator 从后往前
id obj;
while(obj = [enumerator nextObject])
{
[newArray addObject: obj];
}

排序:

\

[newArray sortUsingSelector:@selector(compare:)];

5.NSDictionary\

NSDictionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"One",@"1",@"Two",@"2",@"Three",@"3",nil];
NSString *string = [dictionary objectForKey:@"One"];
[dictionary setObject:@"One" forKey:@"1"];

//删除指定的字典[dictionary removeObjectForKey:@"3"];

 

6.文件夹操作:

\

/*******************************************************************************************
从目录搜索扩展名为jpg的文件
*******************************************************************************************/

//NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *home;
home = @"../Users/";

NSDirectoryEnumerator *direnum;
direnum = [fileManager enumeratorAtPath: home];

NSMutableArray *files = [[NSMutableArray alloc] init];

//枚举
NSString *filename;
while (filename = [direnum nextObject]) {
if([[filename pathExtension] hasSuffix:@"jpg"]){
[files addObject:filename];
}
}

//快速枚举
//for(NSString *filename in direnum)
//{
// if([[filename pathExtension] isEqualToString:@"jpg"]){
// [files addObject:filename];
// }
//}

文章目录
  1. 1. import "ViewControllerB.h"
  2. 2. import "ViewControllerA.h"