UIKit Fragment

Custom Icon and Image Creation Guidelines： https://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/MobileHIG/IconsImages/IconsImages.html

--UILabel
垂直居中
http://tangqiaoboy.blog.163.com/blog/static/1161142582011102010848526/

lab.lineBreakMode = UILineBreakModeWordWrap;
lab.numberOfLines = 0;

lab.adjustsFontSizeToFitWidth = YES;
lab.minimumFontSize = [UIFont systemFontOfSize:8.0];
text.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;

// 自适应宽、高
view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
// 自适应宽，固定top margin位置
view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleTopMargin;

--UISegmentedControl

UISegmentedControl.momentary = YES;不跟踪选中状态
UISegmentedControl.autoresizingMask = UIViewAutoresizingFlexibleWidth;
self.navigationItem.prompt = @" ";

--Button事件关联

	UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
	btn.frame = CGRectMake(0, 0, 320, 55);
	[btn addTarget:self action:@selector(eventButton:) forControlEvents:UIControlEventTouchUpInside];

btn.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;
btn.imageEdgeInsets = UIEdgeInsetsMake(0,0,0,0);
btn.titleEdgeInsets = UIEdgeInsetsMake(0,0,0,0);
contentRectForBound, titleRectForContentRect, imageRectForContentRect

--performSelector

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 
{
    tableSelection = indexPath;
    tapCount++;
    switch (tapCount)
    {
        case 1: //single tap
            [self performSelector:@selector(singleTap) withObject: nil afterDelay: .4];
            break;
        case 2: //double tap
            [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(singleTap) object:nil];
            [self performSelector:@selector(doubleTap) withObject: nil];
            break;
        default:
            break;
    }
}

//   这用得蛮巧的，原理大家都知道，但这么用会少
NSArray * views = [tabBarController.view subviews ];
    for(id v in views) {
        if([v isKindOfClass:[UITabBar class]]){            
            [(UITabBar *)v setHidden:YES];}
}