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Posted by Gao Fei on April 22, 2017

将视图显示在最前方

[self.view addSubview:view]; [self.view bringSubviewToFront:view];

下拉取消回弹效果

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
    
    //限制下拉没有回弹效果
    if (scrollView.contentOffset.y <= 0){
        
        CGPoint point = scrollView.contentOffset;
        point.y = 0;
        [scrollView setContentOffset:point];
    }
}

检测某个API是否可用

1.使用respondsToSelector:方法检测是否有某个方法 respondsToSelector:@selector(method)

  1. 使用<objc/runtime.h>检测是否有某个属性 if (class_getProperty([ClassName class], “propertyName”)) { // it has that property! }