FirstApp，iphone开发学习总结6，Navigation的使用

如图所示，实现的功能：


为了展示，我创建一个NavView文件，里面包含3个View：

@interface NavView1 : UIViewController{//代表View1
}
@end

@interface NavView2 : UIViewController {//代表View2
}
@end

@interface NavView3 : UIViewController {//代表View3
}
@end在NavViewController.m文件中，添加头文件：

#import "NavView.h- (id)init {
self = [super init];
if (self) {
[self setTitle:@"导航标签"];
}
return self;
}在- (void)viewDidLoad中实现：在view添加一个按钮，点击后，push View1。

- (void)viewDidLoad
{
UIButton *navViewBtn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
navViewBtn.frame = CGRectMake(40.0, 30.0, 240.0, 30.0);
[navViewBtn setTitle:@"To View1" forState:UIControlStateNormal];
[navViewBtn addTarget:self action:@selector(pushView:) forControlEvents:UIControlEventTouchUpInside];

[[self view] addSubview:navViewBtn];
}按钮事件实现：

- (void)pushView:(id)sender
{
NavView1 *nv1 = [[NavView1 alloc] init];
[[self navigationController] pushViewController:nv1 animated:YES];
[nv1 release];
}点击按钮后，进入View1，即NavView1，此view拥有一个Button，push至View2：

- (id)init {
self = [super init];
if (self) {
[self setTitle:@"View1"];
}
return self;
}- (void)viewDidLoad
{
UIButton *navViewBtn1 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
navViewBtn1.frame = CGRectMake(40.0, 30.0, 240.0, 30.0);
[navViewBtn1 setTitle:@"To View2" forState:UIControlStateNormal];
[navViewBtn1 addTarget:self action:@selector(pushView:) forControlEvents:UIControlEventTouchUpInside];

[[self view] addSubview:navViewBtn1];
}- (void)pushView:(id)sender
{
NavView2 *nv2 = [[NavView2 alloc] init];
[[self navigationController] pushViewController:nv2 animated:YES];
[nv2 release];
}当点击按钮，此时，进入View2。

View2做的事比较多：

1. 进入View3

2. 到达RootView

3. 到达View1

首先，创建3个按钮，并执行事件：

- (id)init {
self = [super init];
if (self) {
[self setTitle:@"View2"];
}
return self;
}- (void)viewDidLoad
{
UIButton *navViewBtn2 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
navViewBtn2.frame = CGRectMake(40.0, 30.0, 240.0, 30.0);
[navViewBtn2 setTitle:@"Open View3" forState:UIControlStateNormal];
[navViewBtn2 addTarget:self action:@selector(openView:) forControlEvents:UIControlEventTouchUpInside];

UIButton *navViewBtn21 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
navViewBtn21.frame = CGRectMake(40.0, 80.0, 240.0, 30.0);
[navViewBtn21 setTitle:@"To Root" forState:UIControlStateNormal];
[navViewBtn21 addTarget:self action:@selector(popView:) forControlEvents:UIControlEventTouchUpInside];

UIButton *navViewBtn22 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
navViewBtn22.frame = CGRectMake(40.0, 130.0, 240, 30);
[navViewBtn22 setTitle:@"To View1" forState:UIControlStateNormal];
[navViewBtn22 addTarget:self action:@selector(popView1:) forControlEvents:UIControlEventTouchUpInside];

[[self view] addSubview:navViewBtn2];
[[self view] addSubview:navViewBtn21];
[[self view] addSubview:navViewBtn22];
}点击第一个“Open View3”按钮时：

//这里使用presentModalViewController，由下弹出。

//创建UINavigationController的作用是进入此时的View，navigation为空，必须新建一个。

- (void)openView:(id)sender
{
NavView3 *nv3 = [[NavView3 alloc] init];
UINavigationController *nv = [[UINavigationController alloc] initWithRootViewController:nv3];
[self presentModalViewController:nv animated:YES];
[nv release];
[nv3 release];
}点击第二个“To Root”按钮时：//直接进入RootView，此处要检查navigationController是否存在。

- (void)popView:(id)sender
{
[[self navigationController] popToRootViewControllerAnimated:YES];
}点击第三个“To View1”按钮时，后推一位：

- (void)popView1:(id)sender
{
[[self navigationController] popViewControllerAnimated:YES];
} //还有一种– popToViewController:animated:，总体类似，参考

差不多都实现了 ，就剩下如何关闭View3了。NavView3的实现：

- (id)init {
self = [super init];
if (self) {
[self setTitle:@"View3"];
}
return self;
}为了美观点，将按钮添加到Navigation的左边并添加一个Label显示此处为View3：

- (void)viewDidLoad
{
UILabel *navViewLbl3 = [[UILabel alloc] initWithFrame:CGRectMake(110.0, 100.0, 100.0, 30.0)];
navViewLbl3.text = @"View3 Here!!";
navViewLbl3.font = [UIFont fontWithName:@"" size:20];
[[self view] addSubview:navViewLbl3];

UIBarButtonItem *navViewBtn3 = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStyleDone target:self action:@selector(closeView:)];
[self.navigationItem setLeftBarButtonItem:navViewBtn3];
}事件实现：

- (void)closeView:(id)sender
{
[self dismissModalViewControllerAnimated:YES];
}

持续完善，求指点。

To 6 code download：iOS_FirstApp_6.zip