- (void)viewDidLoad {
    [super viewDidLoad];
    
    //步进器 固定的size (94*27), 事件驱动型控件
    UIStepper *st = [[UIStepper alloc] initWithFrame:CGRectMake(10,10,300,30)];
    //设置最大值
    st.maximumValue = 300;
    //设置最小值
    st.minimumValue = 10;
    //设置步长 (默认值为1 必须>0)(+一次增加的值/-一次减少的值)
    st.stepValue = 10;
    st.continuous = NO;
    [st addTarget:self action:@selector(stepperValueChanged:) forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:st];
    
    //进度条,普通视图控件,高度固定9
    UIProgressView *progress = [[UIProgressView alloc] initWithFrame:CGRectMake(10,100,300,30)];
    //进度条的进度属性（默认为0,0.0-1.0），值大于1,进度条一直处于满格状态
    progress.progress = 0.1;
    progress.tag = 101;
    [self.view addSubview:progress];
}
- (void)stepperValueChanged:(UIStepper *)st{
    //点击+/-号value值发生变化
    UIProgressView *progress = (UIProgressView *)[self.view viewWithTag:101];
    progress.progress = st.value/300;
    NSLog(@"stepperValue:%f",st.value);
}