ios开发笔记--状态栏的自定义，隐藏

iOS7 StatusBar 在需要隐藏或改变样式时在UIViewConroller中调用：

 [self setNeedsStatusBarAppearanceUpdate];

1、隐藏

StatusBar在iOS7中无法使用一下接口隐藏：

 [[UIApplication sharedApplication] setStatusBarHidden:YES];

若要隐藏需要在UIViewController中实现下列函数：

 - (BOOL)prefersStatusBarHidden
 {
     return YES;
 }

2、样式改变

iOS 7中statusbar 有两种样式：白色字体UIStatusBarStyleLightContent和黑色字体UIStatusBarStyleDefault。
如果改变需要在UIViewController中实现：

 - (UIStatusBarStyle)preferredStatusBarStyle
 {
     return UIStatusBarStyleDefault;
 }

3、自定义状态栏，方法一

 UIWindow * statusWindow = [[UIWindow alloc] initWithFrame:[UIApplication sharedApplication].statusBarFrame];
     [statusWindow setWindowLevel:UIWindowLevelStatusBar + 1];
     [statusWindow setBackgroundColor:[UIColor clearColor]];

     UILabel * statusLabel = [[UILabel alloc] initWithFrame:statusWindow.bounds];
     statusLabel.text = @"RSSI:";
     statusLabel.textColor = [UIColor blueColor];
     statusLabel.textAlignment = NSTextAlignmentCenter;
     statusLabel.backgroundColor = [UIColor blackColor];

     [statusWindow addSubview:statusLabel];

     [statusWindow makeKeyAndVisible];

4、自定义状态栏，方法二

如果需要在状态栏显示自定义的消息时，就需要自定义状态栏。

代码如下：

XYCustomStatusBar.h

 #import

 @interface XYCustomStatusBar : UIWindow{

     UILabel *_messageLabel;
 }

 - (void)showStatusMessage:(NSString *)message;

 - (void)hide;

 @end

XYCustomStatusBar.m

 #import "XYCustomStatusBar.h"

 @implementation XYCustomStatusBar

 - (void)dealloc{
     [super dealloc];
     [_messageLabel release], _messageLabel = nil;
 }

 - (id)init{
     self = [super init];
     if (self) {
         self.frame = [UIApplication sharedApplication].statusBarFrame;
         self.backgroundColor = [UIColor blackColor];
         self.windowLevel = UIWindowLevelStatusBar + 1.0f;

         _messageLabel = [[UILabel alloc] initWithFrame:self.bounds];
         [_messageLabel setTextColor:[UIColor whiteColor]];
         [_messageLabel setTextAlignment:NSTextAlignmentRight];
         [_messageLabel setBackgroundColor:[UIColor clearColor]];
         [self addSubview:_messageLabel];
     }

     return self;
 }

 - (void)showStatusMessage:(NSString *)message{
     self.hidden = NO;
     self.alpha = 1.0f;
     _messageLabel.text = @"";

     CGSize totalSize = self.frame.size;
     self.frame = (CGRect){ self.frame.origin, 0, totalSize.height };

     [UIView animateWithDuration:0.5 animations:^{
         self.frame = (CGRect){self.frame.origin, totalSize };
     } completion:^(BOOL finished){
         _messageLabel.text = message;
     }];

 }


 - (void)hide{
     self.alpha = 1.0f;

     [UIView animateWithDuration:0.5f animations:^{
         self.alpha = 0.0f;
     } completion:^(BOOL finished){
         _messageLabel.text = @"";
         self.hidden = YES;
     }];
 }

 @end

为了让自定义的状态栏可以让用户看到，设置了它的windowlevel，在ios中，windowlevel属性决定了UIWindow的显示层次，默认的windowlevel为UIWindowLevelNormal，即0.0 。为了能覆盖默认的状态栏，将windowlevel设置高点。其他代码基本上都不解释什么，如果要特殊效果，可以自己添加。