iOS 掌握

1.其实很简单，直接找到官方的关于 App Icons 和 App launchImage的示例进行对比。另外，如果你的.png图片去掉alpha依然有问题，那就改成.jpg图片吧。不要浪费宝贵的时间。
1.点击按钮振动
//点击按钮振动事件
导入#import <AudioToolbox/AudioToolbox.h>
在按钮点击事件中，加入以下代码
//AudioToolBox.framework下的 点击振动
AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);

2.字符串的使用
//获取地址
NSString *filePath = [[[NSBundle mainBundle] bundlePath] stringByAppendingPathComponent:@"zhiKuCaiDesc.txt"];
//获取字符串 读取内容的方式
1.ffilepath转化为字符串
NSString *str = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
2.转化为二进制 二进制转化为字符串
NSData *data = [NSData dataWithContentsOfFile:filePath];
NSString *str=[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
textView.text = str;

3.重新登录的几种方式
1.present 到viewcontroller
MPLoginViewController * loginVC =[[MPLoginViewController alloc]init];
MPNavigationController * nav = [[MPNavigationController alloc]initWithRootViewController:loginVC];
loginVC.isPresentViewController = YES;
[self.window.rootViewController presentViewController:nav animated:YES completion:nil];
返回的时候 用dismiss
2.[self.navigationController pushViewController:VC animated:NO];

//获取Window当前显示的ViewController

• (UIViewController)currentViewController{
  //获得当前活动窗口的根视图
  UIViewController vc = [UIApplication sharedApplication].keyWindow.rootViewController;
  while (1)
  {
  //根据不同的页面切换方式，逐步取得最上层的viewController
  if ([vc isKindOfClass:[UITabBarController class]]) {
  vc = ((UITabBarController)vc).selectedViewController;
  }
  if ([vc isKindOfClass:[UINavigationController class]]) {
  vc = ((UINavigationController)vc).visibleViewController;
  }
  if (vc.presentedViewController) {
  vc = vc.presentedViewController;
  }else{
  break;
  }
  }
  return vc;
  }

2. if (iOS7) {
   // 声明这张图片用原图(别渲染)
   selectedImage = [selectedImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
   }
   //防止图片变成蓝色
   3.[IOS/UINavigation]隐藏UINavigationBar的返回文字
   http://blog.csdn.net/zheng_paul/article/details/51206507
   返回首页
   1.遍历所有的自控制器
   for (UIViewController* v in self.navigationController.viewControllers) {
   if ([v isKindOfClass:[BuyVC class]]) {
   [self.navigationController popToViewController:v animated:YES];
   }
   }

2.//获取Window当前显示的ViewController

• (UIViewController)currentViewController{
  //获得当前活动窗口的根视图
  UIViewController vc = [UIApplication sharedApplication].keyWindow.rootViewController;
  while (1)
  {
  //根据不同的页面切换方式，逐步取得最上层的viewController
  if ([vc isKindOfClass:[UITabBarController class]]) {
  vc = ((UITabBarController)vc).selectedViewController;
  }
  if ([vc isKindOfClass:[UINavigationController class]]) {
  vc = ((UINavigationController)vc).visibleViewController;
  }
  if (vc.presentedViewController) {
  vc = vc.presentedViewController;
  }else{
  break;
  }
  }
  return vc;
  }