專案程式碼分析https://github.com/thanklife/iosChangeViewcontroller

這是一個程式碼實現view的例子：主view上有4個控制元件：3個按鈕和一個UIView型別的contentView，其中點選某一個按鈕的時候，就會在contentView上新增子控制元件進行顯示

#import <UIKit/UIKit.h>

@interface MainViewController : UIViewController
{

    IBOutlet UIView *contentView;

    IBOutlet UIButton *firstButton;

    IBOutlet UIButton *secondButton;

    IBOutlet UIButton *thirdButon;

    UIViewController *currentViewController;

}

-(IBAction)onClickbutton:(id)sender;

@end
 

#import "MainViewController.h"

#import "FirstViewController.h"

#import "SecondViewController.h"

#import "ThirdViewController.h"

@implementation MainViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)didReceiveMemoryWarning
{
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
}

#pragma mark - View lifecycle

FirstViewController *firstViewController;
SecondViewController *secondViewController;
ThirdViewController *thirdViewController;

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    firstViewController=[[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
    [self addChildViewController:firstViewController];

    secondViewController=[[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
    [self addChildViewController:secondViewController];

    thirdViewController=[[ThirdViewController alloc] initWithNibName:@"ThirdViewController" bundle:nil];
    [self addChildViewController:thirdViewController];

    [contentView addSubview:thirdViewController.view];

    currentViewController=thirdViewController;

}

- (void)viewDidUnload
{
    [super viewDidUnload];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
-(IBAction)onClickbutton:(id)sender
{
    if ((currentViewController==firstViewController&&[sender tag]==1)||(currentViewController==secondViewController&&[sender tag]==2) ||(currentViewController==thirdViewController&&[sender tag]==3) ) {
        return;
    }
    UIViewController *oldViewController=currentViewController;
    switch ([sender tag]) {
        case 1:
        {
            NSLog(@"留言及回覆");
            [self transitionFromViewController:currentViewController toViewController:firstViewController duration:1 options:UIViewAnimationOptionTransitionCurlUp animations:^{
            }  completion:^(BOOL finished) {
                if (finished) {
                    currentViewController=firstViewController;
                }else{
                    currentViewController=oldViewController;
                }
            }];
}
            break;
        case 2:
        {
            NSLog(@"生日提醒");
            [self transitionFromViewController:currentViewController toViewController:secondViewController duration:1 options:UIViewAnimationOptionTransitionCurlDown animations:^{

            }  completion:^(BOOL finished) {
                if (finished) {
                  currentViewController=secondViewController;
                }else{
                    currentViewController=oldViewController;
                }
            }];
        }
            break;
        case 3:
        {
            NSLog(@"好友申請");
            [self transitionFromViewController:currentViewController toViewController:thirdViewController duration:1 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{

            }  completion:^(BOOL finished) {
                if (finished) {
                     currentViewController=thirdViewController;
                }else{
                    currentViewController=oldViewController;
                }
            }];
        }
            break;
        default:
            break;
    }
}
@end
 

#import <UIKit/UIKit.h>

@interface FirstViewController : UIViewController

@end

#import "FirstViewController.h"

@implementation FirstViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (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.
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    debugMethod();
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
    debugMethod();
}

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    debugMethod();
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    debugMethod();
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    debugMethod();
}

- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];
    debugMethod();
}

- (void)willMoveToParentViewController:(UIViewController *)parent {
    debugMethod();
}

- (void)didMoveToParentViewController:(UIViewController *)parent {
    debugMethod();
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

@end
 

經過這個內容總結：

1、子控制元件中新增 的view 也可有UIViewController，據目前瞭解的情況，這裡的controller初始化後要儲存，不然addSubview方法之後，就會被釋放；

2、在xib中對這些子控制元件UIView的屬性 simulated metrics--》size要設定為Freeform，status bar top bar，bottom bar可以根據情況進行設定。

3、在執行[self addChildViewController:firstViewController];的時候會呼叫firstViewController 的- (void)willMoveToParentViewController:(UIViewController *)parent方法

4、在執行[contentView addSubview:thirdViewController.view];的時候會執行 -[ThirdViewController viewDidLoad]；

5、當進行addChildViewController的幾個view進行切換的操作的實現是- (void)transitionFromViewController:(UIViewController *)fromViewController toViewController:(UIViewController *)toViewController duration:(NSTimeInterval)duration options:(UIViewAnimationOptions)options animations:(void (^ __nullable)(void))animations completion:(void (^ __nullable)(BOOL finished))completion NS_AVAILABLE_IOS(5_0);

apple文件的註釋內容為：

  This method can be used to transition between sibling child view controllers. The receiver of this method is
  their common parent view controller. (Use [UIViewController addChildViewController:] to create the
  parent/child relationship.) This method will add the toViewController's view to the superview of the
  fromViewController's view and the fromViewController's view will be removed from its superview after the
  transition completes. It is important to allow this method to add and remove the views. The arguments to
  this method are the same as those defined by UIView's block animation API. This method will fail with an
  NSInvalidArgumentException if the parent view controllers are not the same as the receiver, or if the
  receiver explicitly forwards its appearance and rotation callbacks to its children. Finally, the receiver
  should not be a subclass of an iOS container view controller. Note also that it is possible to use the
  UIView APIs directly. If they are used it is important to ensure that the toViewController's view is added
  to the visible view hierarchy while the fromViewController's view is removed.

這裡實現的程式碼是：

            [self transitionFromViewController:currentViewController toViewController:firstViewController duration:1 options:UIViewAnimationOptionTransitionCurlUp animations:^{
            }  completion:^(BOOL finished) {
                if (finished) {
                    currentViewController=firstViewController;
                }else{
                    currentViewController=oldViewController;
                }
            }];

該方法的執行會讓依次執行：

-[SecondViewController viewDidLoad]
-[ThirdViewController viewWillDisappear:]
-[SecondViewController viewWillAppear:]
-[SecondViewController viewDidAppear:]
-[ThirdViewController viewDidDisappear:]

5，這個程式碼部分新增 #define debugMethod() NSLog(@"%s", __func__)的巨集定義，在 view 的一些方法裡面新增後，非常有利於觀察各個方法的呼叫順序，這裡經過觀察就可以更好的進行程式碼的新增和實現了。