從NSDate的

Question

獲取百分之一秒的差異我想兩個觸摸

float starttime; 
float endtime; 

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 

    starttime = [[NSDate date] timeIntervalSince1970]; 

} 

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{ 

     endtime = [[NSDate date] timeIntervalSince1970]; 

     NSLog(@"starttime %f endtime %f",starttime,endtime); 

     float diff = endtime - starttime; 


} 

1. 問題是，我發現這兩個結束時間和開始時間是一樣的，不管我有多長之間在百分之一秒的時間差觸摸，但如果我刪除timeIntervalSince1970，這不是

2. 沒有任何方法來獲取差異

Answer 1

我最好使用

double startTime = CACurrentMediaTime(); 

這是推薦的方式進行相對時機

double starttime; 
double endtime; 

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 

    startTime = CACurrentMediaTime(); 
} 

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{ 

    endtime = CACurrentMediaTime(); 
    NSLog(@"starttime %f endtime %f",starttime,endtime); 
    double diff = endtime - starttime; 
    NSLog(@"Diff - %f", diff); 
}