UISlider生成奇怪的值

Question

我有一個UISlider，我希望允許在0.5和10之間進行選擇。當值更改時觸發設置標籤值的回調函數時，會得到一個奇怪的值範圍。我的代碼是：

-(IBAction)DidChangeSliderValue:(id)sender { 
    NSString *distance = [NSString stringWithFormat:@"%i miles", sdrDistance.value]; 
    lblDistance.text = distance; 
    NSLog(distance); 

我所立爲滑塊如下：

然而，由左到這個正確的結果到日誌拖動：

1-07-12 16:38:24.354 myapp[2758:207] 1073741824 miles 
2011-07-12 16:38:24.355 myapp[2758:207] 0 miles 
2011-07-12 16:38:24.356 myapp[2758:207] 0 miles 
2011-07-12 16:38:27.873 myapp[2758:207] 0 miles 
2011-07-12 16:38:27.890 myapp[2758:207] -1073741824 miles 
2011-07-12 16:38:27.924 myapp[2758:207] -2147483648 miles 
2011-07-12 16:38:27.941 myapp[2758:207] 536870912 miles 
2011-07-12 16:38:27.957 myapp[2758:207] -2147483648 miles 
2011-07-12 16:38:27.991 myapp[2758:207] 1073741824 miles 
2011-07-12 16:38:28.007 myapp[2758:207] -536870912 miles 
2011-07-12 16:38:28.023 myapp[2758:207] 1073741824 miles 
2011-07-12 16:38:28.041 myapp[2758:207] 536870912 miles 
2011-07-12 16:38:28.058 myapp[2758:207] -536870912 miles 
2011-07-12 16:38:28.074 myapp[2758:207] 1073741824 miles 
2011-07-12 16:38:28.091 myapp[2758:207] 536870912 miles 
2011-07-12 16:38:28.141 myapp[2758:207] 0 miles 

是這有什麼合乎邏輯的原因？

Answer 1

[UISlider value]返回float，不是int，所以你必須在你的NSLog語句中使用%f而不是%i。

Answer 2

value是一個浮點數。使用%f而不是%i。

Answer 3

您分配一個int（％I）爲浮點值（％F），因爲uislider是浮點（小數）不是一個int（整數），所以它應該是這樣的：

-(IBAction)DidChangeSliderValue:(id)sender { 
NSString *distance = [NSString stringWithFormat:@"%f miles", sdrDistance.value]; 
lblDistance.text = distance; 
NSLog(distance);