macOS學習記錄 (3)

Xcode3.2環境下

1:字符串連接
an easy app :

a converter class:

@interface Converter : NSObject {

}
-(NSString*)convertAppend:(NSString*)ip newmsg:(NSString*)msg;
@end

////
@implementation Converter-(NSString*)convertAppend:(NSString*)ip newmsg:(NSString*)msg
{
	NSString*s=[NSString stringWithFormat:@"%@%@",ip,msg];
	return s;
	
}
@end

a controller class:

@interface Controller : NSObject {
	IBOutlet id converter;//
	IBOutlet id ipaddressField;
	IBOutlet id chatmsgField;
	IBOutlet id newmsgField;
}
-(IBAction)converter:(id)sender;
@end

////

#import "Controller.h"
#import "Converter.h"

@implementation Controller
//goal: show ipaddress+newmsg
//input: ipaddressField and newmsgField
//output: chatmsgField
-(IBAction)converter:(id)sender
{
	NSString*ip=[ipaddressField stringValue];
	NSString*msg=[newmsgField stringValue];
	NSString*chatmsg=[converter convertAppend:ip newmsg:msg];
	[chatmsgField setString:chatmsg];
	//[chatmsgField setString:[NSString stringWithFormat:@"%@%@",ip,msg]];
}
@end

類命名時大小寫很關鍵，區分identity。下一個練習中，筆者全部用小寫，結果類方法和類名重複，報錯。

2.貨幣轉換器

//聲明模型類Converter，類中有一個計算匯率的實例方法convertAmount
@interface Converter : NSObject {
	
}
-(float)convertAmount:(float)amt atRate:(float)rate;
@end///
#import "Converter.h"

//實現類中的方法
@implementation Converter
-(float)convertAmount:(float)amt atRate:(float)rate
{
	return (amt * rate);
}
@end
///
//聲明控制器類Controller，四個插座變量用於獲取三個文本框，一個模型類的信息
//動作，當按下按鈕時向Controller類發送converter：消息
@interface Controller : NSObject {
	IBOutlet id converter;
	IBOutlet id dollarField;
	IBOutlet id rateField;
	IBOutlet id totalField;
}
-(IBAction)converter:(id)sender;
@end
///
#import "Controller.h"
#import "Converter.h"
//實現動作，當按下按鈕時，獲取兩個文本框當內容作爲參數，調用模型中當方法計算金額，再調用另一個文本框當方法顯示金額
@implementation Controller
-(IBAction)converter:(id)sender
{
	float rate = [rateField floatValue];
	float amt = [dollarField floatValue];
	//float total=(rate*amt);
	float total = [converter convertAmount:amt atRate:rate];
	[totalField setFloatValue:total];
}
@end

字符串與float轉換－參考網友博客
https://www.cnblogs.com/hecheng0314/p/4664175.html