放一些乱起八糟的知识点

ios姿势

左滑返回：
if ([navigation respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
	navigation.interactivePopGestureRecognizer.enabled = YES;
	navigation.interactivePopGestureRecognizer.delegate = nil;
}

键盘收起管理：https://github.com/hackiftekhar/IQKeyboardManager

UITableView空白cell不显示：self.tableView.tableFooterView = [[UIView alloc] init];

ScrollView滑不到顶：self.automaticallyAdjustsScrollViewInsets = NO;  

滑动隐藏导航栏：navigationController.hidesBarsOnSwipe = Yes

导航返回按钮文字去除：
[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
													 forBarMetrics:UIBarMetricsDefault];
													 
CollectionView悬停header：https://github.com/jamztang/CSStickyHeaderFlowLayout

uitextfield placeholder颜色和位置：
- (void) drawPlaceholderInRect:(CGRect)rect {  
	[[UIColor blueColor] setFill];  
	[self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation 
				   	   alignment:self.textAlignment];  
}  

NSTimer因界面有动画和操作导致延迟执行解决：[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];