IOS开发笔记(六)---对iOS多视图开发的初步了解

今天看了一下iOS开发中多个视图的应用.

iOS下包含了几种不同种类的视图类型和controller:比如Tab Bar ,Navigation Bar ,Tool Bar等.也可以自定义自己的视图的controller

程序中主窗口的视图控制器我们成为root controller,由它负责不同视图的切换等功能.

由root controller负责的视图都有自己的controller和delegate,比如一个tab bar,当用户在tab bar上点击的时候,是由tab bar的controller负责处理,而当用户在内容界面点击的时候,是由内容视图的controller负责处理的.

书中的例子很简单,点击tab bar中的按扭,在两个背景颜色(一蓝一黄)的视图中切换,两个视图中各有一个button

书中的例子建立的步骤如下:

1.建立一个Window base application ,没有view controller,只有一个window

2.添加视图文件

3.添加xib文件

4.在AppDelegate中添加一个IBOutlet,

@property (nonatomic, retain) IBOutlet SwitchViewController *switchViewController; 5.为了将主视图SwitchViewController和Window关联,需要使用addSubview,添加了以下代码: #import "View_SwitcherAppDelegate.h"
#import "SwitchViewController.h"
@implementation View_SwitcherAppDelegate
@synthesize window;
@synthesize switchViewController;
- (void) application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
// Override point for customization after application launch
[self.window addSubview:switchViewController.view];
[self.window makeKeyAndVisible];
return YES; //注:书中代码这样写的,返回YES 但是函数类型是void.经查SDK,发现函数类型是BOOL
}
- (void)dealloc {
[window release];
[switchViewController release];
[super dealloc];
} 6. 为了切换两个view,我们在SwitchViewController里添加两个View的指针,不定义IBOutlet,同时定义方法switchViews #import <UIKit/UIKit.h>
@class YellowViewController;
@class BlueViewController;
@interface SwitchViewController : UIViewController {
}
@property (retain, nonatomic) YellowViewController *yellowViewController;
@property (retain, nonatomic) BlueViewController *blueViewController;
- (IBAction)switchViews:(id)sender;
@end 7.代码架构好了,开始在IB中操作 8. 在IB中将AppDelegate中的IBOutlet switchViewController与类SwitchViewController链接 9. 修改SwitchViewController.m 主要就是从Nib加载ViewController,不用的释放Controller 刚开始只加载BlueView,因为YellowView可能用户不会选择,等到切换的时候才加载(Lazy Loading) #import "SwitchViewController.h"
#import "YellowViewController.h"
#import "BlueViewController.h"
@implementation SwitchViewController
@synthesize yellowViewController;
@synthesize blueViewController;
- (void)viewDidLoad
{
BlueViewController *blueController = [[BlueViewController alloc]
initWithNibName:@"BlueView" bundle:nil];
self.blueViewController = blueController;
[self.view insertSubview:blueController.view atIndex:0];
[blueController release];
[super viewDidLoad];
}
- (IBAction)switchViews:(id)sender
{
if (self.yellowViewController.view.superview == nil)
{
if (self.yellowViewController == nil)
{
YellowViewController *yellowController =
[[YellowViewController alloc] initWithNibName:@"YellowView"
bundle:nil];
self.yellowViewController = yellowController; [yellowController release];
}
[blueViewController.view removeFromSuperview];
[self.view insertSubview:yellowViewController.view atIndex:0];
}
else
{
if (self.blueViewController == nil)
{
BlueViewController *blueController =
[[BlueViewController alloc] initWithNibName:@"BlueView"
bundle:nil];
self.blueViewController = blueController;
[blueController release];
}
[yellowViewController.view removeFromSuperview];
[self.view insertSubview:blueViewController.view atIndex:0];
}
}

Releases the view if it doesn't have a superview
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview
[super didReceiveMemoryWarning];
// Release any cached data, images, etc, that aren't in use
if (self.blueViewController.view.superview == nil)
self.blueViewController = nil;
else
self.yellowViewController = nil;
} - (void)dealloc {
[yellowViewController release];
[blueViewController release];
[super dealloc];
}
@end 10.完善两个内容视图,添加button,弹出不同的内容提示. #import <UIKit/UIKit.h>
@interface BlueViewController : UIViewController {
}
- (IBAction)blueButtonPressed;
@end 在实现中加入UIAlertView即可.(略去)

打开BlueView.nib,在Indentity Inspector中选择class name为BlueViewController,表明从nib从BlueViewController

然后修改View的背景色,更改View的位置在属性页的

Simulated User Interface Elements选项下 11.加入视图切换动画 - (IBAction)switchViews:(id)sender
{
[UIView beginAnimations:@"View Flip" context:nil];
[UIView setAnimationDuration:1.25];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];

.....

if(..) { [UIView setAnimationTransition:
UIViewAnimationTransitionFlipFromRight
forView:self.view cache:YES];
[blueViewController viewWillAppear:YES];
[yellowViewController viewWillDisappear:YES]; … … }

[UIView commitAnimations]; }