OC入門教程

一、入門教程

入門教程1
入門教程2

二、類基本用法

@interface MyObject : NSObject {  //聲明interface
    int memberVar1; // 實體變量 默認protected屬性
    id  memberVar2;
    @public      //自定義public屬性
    NSString *name;
}

+(return_type) class_method; // 類方法，類似static

-(return_type) instance_method1; // 實例方法
-(return_type) instance_method2: (int) p1;
-(return_type) instance_method3: (int) p1 andPar: (int) p2;
@end


@implementation MyObject {  //定義implementation
  int memberVar3; //默認private屬性
}

+(return_type) class_method {
    .... //method implementation
}
-(return_type) instance_method1 {
     ....
}
-(return_type) instance_method2: (int) p1 {
    ....
}
-(return_type) instance_method3: (int) p1 andPar: (int) p2 {
    ....
}
@end


調用方法示例: 
MyObject *justTest =[MyObject alloc]; 

//實例方法
[justTest instance_method1 ]; 
...

//類方法可直接使用類名調用// 
[MyObject class_method]; 


協議（純虛繼承，需要實現接口的方法）
@protocol Locking //協議
- (void)lock;
- (void)unlock;
@end

@interface SomeClass : SomeSuperClass <Locking>
@end

@implementation SomeClass
- (void)lock {
  // 實現lock方法...
}
- (void)unlock {
  // 實現unlock方法...
}
@end

三、協議與委託

#import <Foundation/Foundation.h> 
@protocol PrintProtocolDelegate 
    - (void)processCompleted; 
@end 

//委託的作用：一個類如PrintClass類調用結束後，通知使用它的另外一個類SampleClass
@interface PrintClass :NSObject { 
    id delegate; 
} 
- (void) printDetails; 
- (void) setDelegate:(id)newDelegate; 
@end 

@implementation PrintClass 
- (void)printDetails { 
    NSLog(@"Printing Details"); 
    [delegate processCompleted]; 
} 
- (void) setDelegate:(id)newDelegate { 
    delegate = newDelegate; 
} 
@end

@interface SampleClass:NSObject<PrintProtocolDelegate> 
- (void)startAction; 
@end 

@implementation SampleClass 
- (void)startAction { 
    PrintClass *printClass = [[PrintClass alloc]init]; 
    [printClass setDelegate:self]; 
    [printClass printDetails]; } 
-(void)processCompleted { 
    NSLog(@"Printing Process Completed"); 
} 
@end 

int main(int argc, const char * argv[]) 
{ 
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; 
    SampleClass *sampleClass = [[SampleClass alloc]init]; 
    [sampleClass startAction]; 
    [pool drain]; 
    return 0; 
}

四、動態調用

- setMyValue:(id) foo;  //id形態表示參數"foo"可以是任何類的實例
- setMyValue:(id <aProtocol>) foo; //id<aProtocol>表示"foo"可以是任何類的實例，但必須採納"aProtocol"協議
- setMyValue:(NSNumber*) foo;  //該聲明表示"foo"必須是"NSNumber"的實例

六、iOS - NSLog打印（精準打印）

https://www.jianshu.com/p/5b5798976feb
NSLog(@“打印字符串：%@”,name);
NSLog(@“打印整形：%i”,number);//或者 %li ; %ld ; %d
NSLog(@“打印字符：%c”,c);
NSLog(@“打印單浮點數：%f”,f);
NSLog(@“打印精度浮點數：%.2f”,f);
NSLog(@“BOOL–b-->%@”,isYES?@“YES”😡“NO”);//打印布爾類型

七、字符串基本操作

https://blog.csdn.net/wangyurui_wyr/article/details/52457534
    NSString *str1 = @"mingtian*";
    NSString *str2 = @"nihao*";
    NSString *str3 = [NSString stringWithFormat:@"%@%@",str1,str2];

八、數據轉換

Object - C 入門 之 數據類型詳解https://blog.csdn.net/shulianghan/article/details/38544659
NSDictionary、NSMutableDictionary的各種實用的用法以及枚舉
https://blog.csdn.net/ylwdi/article/details/46814523
https://blog.csdn.net/u014220518/article/details/50945177

1、  Int 轉NSNumber
int iValue；
NSNumber *number = [NSNumber numberWithInt:iValue];
2、 NSNumber 轉Int
int myInt = [number intValue];；
3、NSString轉int
NSString *stringInt = @“120”;
int ivalue = [stringInt intValue];
4、int轉NSString
NSString *string = [NSString stringWithFormat:@"%d",ivalue];

NSString用法
//1.基本用法
NSString *greeting = @"Hello";

//2.nstring添加字符串
NSString* string; // 結果字符串
NSString* string1, string2; //已存在的字符串，需要將string1和string2連接起來

//方法1. 
string = [NSString initWithFormat:@"%@,%@", string1, string2 ];

//方法2. 
string = [string1 stringByAppendingString:string2];

//方法3 . 
string = [string stringByAppendingFormat:@"%@,%@",string1, string2];

九、# \Log
#import <Foundation/Foundation.h>
int main()
{
NSLog(@“File :%s\n”, FILE );
NSLog(@“Date :%s\n”, DATE );
NSLog(@“Time :%s\n”, TIME );
NSLog(@“Line :%d\n”, LINE );
NSLog(@“ANSI :%d\n”, STDC );
return 0;
}

十、類別（使用已有的類，爲他增加新的方法屬性）

#import <Foundation/Foundation.h>
@interface NSString(MyAdditions)
+(NSString *)getCopyRightString; //類似NNString，爲該類增加方法
@end

@implementation NSString(MyAdditions) +(NSString *)getCopyRightString {
return @“Copyright y ii bai.com 2019”;
}
@end
int main(int argc, const char * argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSString *copyrightString = [NSString getCopyRightString];
NSLog(@“Accessing Category: %@”,copyrightString); [pool drain];
return 0;
}

十一、擴展（類似類別，不過只能使用正在寫的類）

#import <Foundation/Foundation.h>
@interface SampleClass : NSObject {
NSString *name;
}

• (void)setInternalID;
• (NSString *)getExternalID;
  @end

@interface SampleClass() { //擴展上面的了類，和類別作用一樣，區別就是擴展需要在同一文檔中。
NSString *internalID;
}
@end

@implementation SampleClass

• (void)setInternalID {
  internalID = [NSString stringWithFormat: @“UNIQUEINTERNALKEY%dUNIQUEINTERNALKEY”,arc4random()%100];
  }
• (NSString *)getExternalID {
  return [internalID stringByReplacingOccurrencesOfString: @“UNIQUEINTERNALKEY” withString:@""];
  }

十二、複合對象（把已有的對象類拿出來，封裝爲另一個類，進行操作）

oc調用c++
https://blog.csdn.net/u010008647/article/details/78318628

警告：
used as the name of the previous parameter rather than as part of the selector 多爲傳入多個變量沒有空格引起，在第二變量的冒號前面加個空格既可以解決。

ios調用c++出現iostream file not found錯誤
解決方法：將調用的m文件改爲mm文件，將ViewController.m改爲ViewController.mm
https://blog.csdn.net/jasonblog/article/details/7880841