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Objective-C语言应用开发基础编程入门

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字符串

NSString *name = @"jikexueyuan";

以’%@’代表对象

NSLog(@"Hello Objective-C");
NSLog(@"The number is %d",1000);
NSLog(@"Hello %s","XiaoLi");
NSLog(@"Hello %@",name);
NSLog(@"ObjC Object %@",[[[NSObject alloc] init] description]); //实际上是调用NSObject中的description方法

Class的构成

.h file

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@interface People : NSObject{
    int _age;
    NSString *_name;
}
// class method-------------------------------
+(People*)peopleWithAge:(int)age andName:(NSString*)name;
-(id)initWithAge:(int)age andName:(NSString*)name;
-(int)getAge;
-(NSString*)getName;

.m file

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+(People*)peopleWithAge:(int)age andName:(NSString *)name{
    return [[People alloc] initWithAge:age andName:name];
}
- (instancetype)initWithAge:(int)age andName:(NSString *)name
{
    self = [super init];
    if (self) {
        _age = age;
        _name = name;
    }
    return self;
}
-(int)getAge{
    return _age;
}
-(NSString*)getName{
    return _name;
}

call method

Hello *h = [[Hello alloc] init];
[h sayHello];

数组与字典

非可变数组

//三种构造方法，可以从plist文件中获取数据
NSArray *arr = @[@"Hello",@"jikexueyuan"];
NSArray *arr = [NSArray arrayWithObjects:@"Hello", @"jikexueyuan",nil];
NSArray *arr = [NSArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"data" ofType:@"plist"]];

for (int i=0; i<[arr count]; i++) {
    NSLog(@"%@",[arr objectAtIndex:i]);
}

可变数组

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

for (int i=0; i<100; i++) {
    [arr addObject:[NSString stringWithFormat:@"Item %d",i]];
}

NSLog(@"%@",arr);

数组的plist文件

数组的plist文件

字典的plist文件

字典的plist文件

字典与可变字典

//字典的构造
NSDictionary *dict = @{@"name": @"ZhangSan",@"sex":@"male"};    
NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"data" ofType:@"plist"]];
NSLog(@"%@",[dict objectForKey:@"age"]);

//可变字典
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
[dict setObject:@"jikexueyuan" forKey:@"name"];

NSLog(@"%@",[dict objectForKey:@"name"]);

protocol

.h file

#import <Foundation/Foundation.h>

@protocol IPeople <NSObject>

-(int)getAge;
-(void)setAge:(int)age;
-(NSString*)getName;

@end

.m file

@interface Man : NSObject<IPeople>{
int _age;
}

-(id)init;

-(void)setAge:(int)age;
-(NSString*)getName;
-(int)getAge;

@property id<ManDelegate> delegate;

@end

Exception

@try {

    //需要被捕获异常的代码
    @throw [NSException exceptionWithName:@"My Error" reason:nil userInfo:nil];
}
@catch (NSException *exception) {

    //输出一场信息
    NSLog(@"%@",exception);
}
@finally {
    //无论是否有异常，都要执行
    NSLog(@"run");
}