//PlaceholderTextView.m //Copyright (c) All rights reserved. #import"Pla...

1.通过KVC设置默认文本的颜色 textField.placeholder=@"多个标签用逗号或者换行隔开"; //设置了占位文字内容以后,才...

GCD定时器不受RunLoop影响，比NSTimer更精确 //获得队列 //dispatch_queue_t queue = dispatch...

- (void)viewDidLoad { dispatch_async(dispatch_get_global_queue(DISPATCH_...

UIBackgroundTaskIdentifier task =[application beginBackgroundTaskWithExp...

用push，然后做出present的效果 ViewController*vc = [[ViewController alloc] init]; ...

//XMGTopWindow.m #import"XMGTopWindow.h" @implementationXMGTopWindow sta...

文件和目录 cd /home 进入 '/ home' 目录' cd .. 返回上一级目录 cd ../.. 返回上两级目录 cd 进入个人的主目...