macOS學習筆記（5）鍵值編碼和表格視圖

1.如圖，顯示錶格。（說明：代碼來自cocoa入門第二版，環境是xcode3，僅用於學習object－c語法，運行在高版本xcode6.2沒有預期效果。）
FoodItem.h

#import <Cocoa/Cocoa.h>


@interface FoodItem : NSObject {
    NSString *name;
    NSNumber *price;
}
-(NSString*)name;
-(void)setName:(NSString*)newname;
-(NSNumber*)price;
-(void)setPrice:(NSNumber*)newprice;
@end

FoodItem.m

#import "FoodItem.h"


@implementation FoodItem

-(id)init
{
    [super init];
    [self setName:@"new item"];
    [self setPrice:[NSNumber numberWithFloat:0.0]];
    return self;
}
-(NSString*)name
{
    return name;
}
-(void)setName:(NSString*)newname
{
    [newname retain];
    [name release];
    name=newname;
}
-(NSNumber*)price
{
    return price;
}
-(void)setPrice:(NSNumber*)newprice
{
    [newprice retain];
    [price release];
    price=newprice;
}

@end

MyDataSource.h

#import <Cocoa/Cocoa.h>


@interface MyDataSource : NSObject {
    NSMutableArray* items;
}

@end

MyDataSource.m

#import "MyDataSource.h"
#import "FoodItem.h"

@implementation MyDataSource
-(id)init
{
    FoodItem *chimi=[[FoodItem alloc] init];
    FoodItem *fajitas=[[FoodItem alloc] init];
    
    [chimi setName:@"chimichange"];
    [chimi setPrice:[NSNumber numberWithFloat:8.95]];
    [fajitas setName:@"fajitaschange"];
    [fajitas setPrice:[NSNumber numberWithFloat:10.95]];
    NSLog(@"%@\n%@",chimi.name,fajitas.name);
    
    items=[[NSMutableArray alloc] init];
    [items addObject:chimi];
    [items addObject:fajitas];
    
    [chimi release];
    [fajitas release];
    
    return self;
}
-(NSInteger)numberOfRowsInTableView:(NSTableView*)tableView
{
    return [items count];
    //return 5;
}
- (id)tableView:(NSTableView*)tableView
objectValueForTableColumn:(NSTableColumn*)tableColumn
            row:(NSInteger)row
{
    NSString*identifier=[tableColumn identifier];
    FoodItem*item=[items objectAtIndex:row];
    return [item valueForKey:identifier];
}
- (void)tableView:(NSTableView*)tableView
   setObjectValue:(id)object
   forTableColumn:(NSTableColumn *)tableColumn
			  row:(NSInteger)row
{
    NSString*identifier=[tableColumn identifier];
    FoodItem*item=[items objectAtIndex:row];
    [item setValue:object forKey:identifier];
}

@end

新建工程，實現按下按鈕顯示最新時間：

#import “Mycontroller.h”

@implementation Mycontroller
-(void)awakeFromNib
{
[textField setObjectValue:[NSCalendarDate date]];
}
-(IBAction)refresh:(id)sender
{
[textField setObjectValue:[NSCalendarDate date]];
}
@end