OS X开发就是苹果电脑上的界面开发：与之前学习OC最大的区别是有了界面，不只是一个输出的框。利用拖界面而自动创建IBOutlet NSTextField和(id)sender类型。

 

ViewController.h文件：

#import <Cocoa/Cocoa.h>

@interface ViewController : NSViewController

@property (weak) IBOutlet NSTextField *weizimu;

@property (weak) IBOutlet NSTextField *shouzimu;@property (weak) IBOutlet NSTextField *xiaoxie;@property (weak) IBOutlet NSTextField *daxie;@property (weak) IBOutlet NSTextField *string;

- (IBAction)change:(id)sender;

@end

ViewController.m文件：

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view.

}

- (void)setRepresentedObject:(id)representedObject {

    [super setRepresentedObject:representedObject];

    // Update the view, if already loaded.

}

- (IBAction)change:(id)sender {

    NSLog(@"%@",[ _string stringValue]);      NSLog(@"%@",[ _string stringValue] lowercaseString]);    NSLog(@"%@",[ _string stringValue] uppercaseString]);

   //  (通过setStringValue进行设置输出)-----（重点）

    [_daxie setStringValue:[[_string stringValue] uppercaseString]];

    [_xiaoxie setStringValue:[[_string stringValue] lowercaseString]];    [_shouzimu setStringValue:[[_string stringValue] capitalizedString]];

   

    NSRange range=NSMakeRange([[_string stringValue] length]-1,1);    NSMutableString *xiao=[NSMutableString stringWithFormat(@"%@",[ _string stringValue] lowercaseString]];

    [_weizimu setStringValue:[[xiao substringWithRange:range]capitalizedString]];

    [xiao replaceCharactersInRange:range withString:[[xiao substringWithRange:range]capitalizedString]];    [_weizimu setStringValue:xiao];

}

@end