UISlider产生奇怪的价值观

Question

我有一个UISlider，我想允许在0.5和10之间进行选择。当回调被触发以在值改变时设置标签的值时，我得到一个奇怪的值范围。我的代码是：

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

我将滑块设置如下：

但是，从左向右拖动会导致日志：

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

这有什么合理的理由吗？

Answer 1

value是一个浮点数。使用%f代替%i。

Answer 2

[UISlider value]会返回float，而不是int，因此您必须在NSLog语句中使用%f而不是%i。

Answer 3

您正在为浮点值（％f）分配一个int（％i），因为uislider是一个浮点数（小数）而不是一个int（整数）所以它应该是这样的：

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