iOS疯狂详解之自定义状态栏代码解析

公司的开发的项目要求在状态栏上边加入程序下载的进度条,之前写的程序,由于是根据ipad的朝向来设置自定义的状态栏的frame,以及子视图的 frame和transform,出现一些不太容易解决的bug。这两天正好项目不太紧,就好好学习一下这方面的知识,以下是我所总结的一点经验:

这里说明一下,Apple没有开放的状态栏的API,在ios 的官方文档没有提到修改Window Level的方式;

先看一下Window Level的可用的值包括:

 1: typedef CGFloat UIWindowLevel;
 2: const UIWindowLevel UIWindowLevelNormal; // 0.0
 3: const UIWindowLevel UIWindowLevelAlert; // 2000.0
 4: const UIWindowLevel UIWindowLevelStatusBar; // 1000.0

默认我们的UIView layer都是在UIWindowLevelNormal上,这也就是为什么系统弹出来的对话框在我们的视图之上,因为它的Window Level级别更高。

根据WindowLevel的原理我们也就知道,如果想在系统的状态栏上,添加自定义的状态栏,就需要比UIWindowLevelStatusBar的级别更高,接下来,用代码说明一下:

首先,先建一个Single View Application,名字自定义就可以了,

然后,新建一个类命名为: StatusBarOverlay 继承自UIWindow类,代码:

StatusBarOverlay.h文件

 1: #import <Foundation/Foundation.h>
 2:  
 3: @interface StatusBarOverlay : UIWindow{
 4:  UIView *contentView;
 5:  UILabel *textLabel;
 6: }
 7:  
 8: @property (nonatomic, retain) UIView *contentView;
 9:  
 10: @property (nonatomic, retain) UILabel *textLabel;
 11:  
 12: @end

StatusBarOverlay.m文件

 1: //
 2: //  StatusBarOverlay.m
 3: //  StatusBarDemo
 4: //
 5: //  Created by jordy wang on 12-8-7.
 6: //  Copyright (c) 2012年 __MyCompanyName__. All rights reserved.
 7: //
 8:  
 9: #import "StatusBarOverlay.h"
 10:  
 11: #define STATUS_BAR_ORIENTATION [UIApplication sharedApplication].statusBarOrientation
 12: #define ROTATION_ANIMATION_DURATION [UIApplication sharedApplication].statusBarOrientationAnimationDuration
 13:  
 14:  
 15: @interface StatusBarOverlay()
 16:  
 17: - (void)initializeToDefaultState;
 18: - (void)rotateStatusBarWithFrame:(NSValue *)frameValue;
 19: - (void)setSubViewHFrame;
 20: - (void)setSubViewVFrame;
 21: @end
 22:  
 23:  
 24: @implementation StatusBarOverlay
 25: @synthesize contentView;
 26: @synthesize textLabel;
 27:  
 28: //重写init方法
 29: - (id)init
 30: {
 31:  self = [super initWithFrame:CGRectZero];
 32:  if (self) {
 33:  self.windowLevel = UIWindowLevelStatusBar + 1;
 34:  self.frame = [UIApplication sharedApplication].statusBarFrame;
 35:  [self setBackgroundColor:[UIColor orangeColor]];
 36:  [self setHidden:NO];
 37: 
 38:  //内容视图
 39:  UIView *_contentView = [[UIView alloc] initWithFrame:self.bounds];
 40:  self.contentView = _contentView;
 41:  [self.contentView setAutoresizingMask:UIViewAutoresizingFlexibleWidth];
 42:  [self.contentView setBackgroundColor:[UIColor cyanColor]];
 43:  [self addSubview:self.contentView];
 44:  [_contentView release];
 45: 
 46: 
 47:  //添加textLabel
 48:  UILabel *_textLabel = [[UILabel alloc] initWithFrame:CGRectMake(30, 0, CGRectGetWidth(self.frame)-60, CGRectGetHeight(self.frame))];
 49:  self.textLabel = _textLabel;
 50:  [self.textLabel setBackgroundColor:[UIColor blueColor]];
 51:  [self.textLabel setFont:[UIFont systemFontOfSize:12]];
 52:  [self.textLabel setTextAlignment:UITextAlignmentCenter];
 53:  [self.textLabel setTextColor:[UIColor blackColor]];
 54:  [self.textLabel setText:@"自定义的状态栏 author by jordy"];
 55:  [self.contentView addSubview:self.textLabel];
 56:  [_textLabel release];
 57: 
 58:  //注册监听---当屏幕将要转动时,所出发的事件(用于操作本视图改变其frame)
 59:  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(willRotateScreenEvent:) 

name:UIApplicationWillChangeStatusBarFrameNotification object:nil];
 60:  //初始化
 61:  [self initializeToDefaultState];
 62:  }
 63: 
 64:  return self;
 65: }
 66:  
 67:  
 68:  
 69:  
 70: //初始化为默认状态
 71: - (void)initializeToDefaultState
 72: {
 73:  //获取当前的状态栏位置
 74:  CGRect statusBarFrame = [UIApplication sharedApplication].statusBarFrame;
 75:  //设置当前视图的旋转, 根据当前设备的朝向
 76:  [self rotateStatusBarWithFrame:[NSValue valueWithCGRect:statusBarFrame]];
 77: 
 78: 
 79: 
 80: }
 81:  
 82:  
 83: //旋转屏幕
 84: - (void)rotateStatusBarWithFrame:(NSValue *)frameValue
 85: {
 86:  CGRect frame = [frameValue CGRectValue];
 87:  UIInterfaceOrientation orientation = STATUS_BAR_ORIENTATION;
 88: 
 89:  if (orientation == UIDeviceOrientationPortrait) {
 90:  self.transform = CGAffineTransformIdentity; //屏幕不旋转
 91:  [self setSubViewVFrame];
 92:  }else if (orientation == UIDeviceOrientationPortraitUpsideDown) {
 93:  self.transform = CGAffineTransformMakeRotation(M_PI); //屏幕旋转180度
 94:  [self setSubViewVFrame];
 95:  }else if (orientation == UIDeviceOrientationLandscapeRight) {
 96:  self.transform = CGAffineTransformMakeRotation((M_PI * (-90.0f) / 180.0f)); //屏幕旋转-90度
 97:  [self setSubViewHFrame];
 98:  }else if (orientation == UIDeviceOrientationLandscapeLeft){
 99:  self.transform = CGAffineTransformMakeRotation(M_PI * 90.0f / 180.0f); //屏幕旋转90度
 100:  [self setSubViewHFrame];
 101:  }
 102: 
 103:  self.frame = frame;
 104:  [self.contentView setFrame:self.bounds];
 105: }
 106:  
 107: //设置横屏的子视图的frame
 108: - (void)setSubViewHFrame
 109: {
 110:  self.textLabel.frame = CGRectMake(30, 0, 1024-60, 20);
 111: }
 112: //设置竖屏的子视图的frame
 113: - (void)setSubViewVFrame
 114: {
 115:  self.textLabel.frame = CGRectMake(30, 0, 748-60, 20);
 116: }
 117:  
 118: #pragma mark -
 119: #pragma mark 响应屏幕即将旋转时的事件响应
 120: - (void)willRotateScreenEvent:(NSNotification *)notification
 121: {
 122:  NSValue *frameValue = [notification.userInfo valueForKey:UIApplicationStatusBarFrameUserInfoKey];
 123:  [self rotateStatusBarAnimatedWithFrame:frameValue];
 124: }
 125:  
 126: - (void)rotateStatusBarAnimatedWithFrame:(NSValue *)frameValue {
 127:  [UIView animateWithDuration:ROTATION_ANIMATION_DURATION animations:^{
 128:  self.alpha = 0;
 129:  } completion:^(BOOL finished) {
 130:  [self rotateStatusBarWithFrame:frameValue];
 131:  [UIView animateWithDuration:ROTATION_ANIMATION_DURATION animations:^{
 132:  self.alpha = 1;
 133:  }];
 134:  }];
 135: }
 136:  
 137: - (void)dealloc
 138: {
 139:  [[NSNotificationCenter defaultCenter] removeObserver:self];
 140:  [textLabel release];
 141:  textLabel = nil;
 142: 
 143:  [contentView release];
 144:  contentView = nil;
 145: 
 146:  [super dealloc];
 147: }
 148:  
 149: @end

由于代码比较简单,并且我在上述代码里有相应的注释,这里需要说明一点的是,默认我们继承自UIWindow的StatusBarOverlay类是hidden状态,需要在初始化的时候设置它的hidden属性为NO,

在屏幕旋转过程中,自定义的状态栏与UIViewController之间的旋转是分离的,所以我们需要做一个隐藏的动画,在旋转过程前先隐藏自定义的状态栏,旋转结果后设置显示状态。

如果需要做一种动画,比方从底部下移显示一条信息,隔N秒后又自动收回的动画,直接设置自定义的视图的y坐标就可以了,默认y坐标设置是0。

最后, 使用它的方式也比较简单,只需要初始化,代码:

StatusBarOverlay *statusBarOverlay = [[StatusBarOverlay alloc] init];

由于我公司的需求是开机自动下载的功能,所以我在初始化的时候,是放在了AppDelegate中。

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