When app start up, use splashView with ActivityIndicatorView

Add SplashScreenVC class in the project.

Use the below code to replace the original code in yourAppDelegate.m:

- (void)applicationDidFinishLaunching:(UIApplication *)application

{

    SplashScreenVC *splashScreenVC = [[SplashScreenVC alloc] initWithNibName:@"SplashScreenVC" bundle:nil];

    self.window.rootViewController = splashScreenVC;

    [self.window makeKeyAndVisible];

}

In SplashScreenVC, import yourAppDelegate.h and add the below code:

-(void)viewDidAppear:(BOOL)animated{

    [super viewDidAppear:animated];

    [self performSelector:@selector(gotoRootVC) withObject:nil afterDelay:1.0];

}

-(void)gotoRootVC

{

    

    SQLiteTutorialAppDelegate *delegate = (SQLiteTutorialAppDelegate *)[UIApplication sharedApplication].delegate;

    delegate.window.rootViewController = delegate.tabBarController;

    [delegate.window makeKeyAndVisible];

}

-(void)viewDidLoad

{

    CGRect r = [UIScreen mainScreen].applicationFrame;

    UIView *activityView = [[[UIView alloc] initWithFrame:r] autorelease];

    self.view = activityView;

    

    activityView.backgroundColor = [UIColor blackColor];

    activityView.alpha = 0.5;

    

    UIImageView *imgView = [[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yourImage.png"]] autorelease];

    [activityView addSubview:imgView];

    

    CGRect wheelR = CGRectMake(r.size.width / 2 - 12, r.size.height / 2 - 12, 24, 24);

    UIActivityIndicatorView *activityWheel = [[UIActivityIndicatorView alloc] initWithFrame:wheelR];

    activityWheel.activityIndicatorViewStyle = UIActivityIndicatorViewStyleWhite;

    activityWheel.autoresizingMask = (UIViewAutoresizingFlexibleLeftMargin |

                                      UIViewAutoresizingFlexibleRightMargin |

                                      UIViewAutoresizingFlexibleTopMargin |

                                      UIViewAutoresizingFlexibleBottomMargin);

    [activityWheel startAnimating];

    [activityView addSubview:activityWheel];

}

UIActivityIndicatorView

網路傳輸時 UIActivityIndicatorView 的動作

這已經是習慣了，大家都習慣要有這個符號出現。

當你的程式有使用到網路傳輸，通常就需要放一個 UIActivityIndicatorView 在畫面上，讓使用者知道目前正在傳輸中，以免讓人覺得沒有回應，像是當機一樣。

可是，為何你照著書本範例加到自己的程式卻不會動呢？

原因是：UIKit 的 main thread 一次只有做一件事，如果你在 ViewController 傳輸檔案，那麼其他的動作會等傳輸完之後再接下去做，所以你要另外再生出一個 thread 去處理 UIActivityIndicatorView 的動作。

首先，在 .h 檔的 @interface 內加上

UIActivityIndicatorView *activityIndicator;

以及

@property (nonatomic, retain) UIActivityIndicatorView *activityIndicator;

另外，再加上兩個 method

-(void)actIndicatorBegin;

-(void)actIndicatorEnd;

開啓 .m 檔，在 @implementation 的下面加上

@synthesize activityIndicator;

在 (void)loadView 內把你的 UIActivityIndicatorView 加上去你要的 View 上面，我這裡加在 UIToolbar 工具列裡面的一個 UIBarButtonItem 按鈕

activityIndicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(0, 0, 24, 24)];

[activityIndicator setCenter:CGPointMake(12, 12)];

[activityIndicator setHidesWhenStopped:YES];

[activityIndicator setActivityIndicatorViewStyle: UIActivityIndicatorViewStyleWhite];

[activityIndicator startAnimating];

UIBarButtonItem *activityItem = [[[UIBarButtonItem alloc] initWithCustomView: activityIndicator]autorelease];

再把這個 UIBarButtonItem 加到 UIToolbar 內

NSArray *items = [NSArray arrayWithObjects:activityItem, nil];

toolbarTop.items = items;

在處理網路傳輸之前先執行這個 thread

[NSThread detachNewThreadSelector: @selector(actIndicatorBegin) toTarget:self withObject:nil];

//需要時間下載檔案的程式寫在這裡

url = [NSURL URLWithString:@"http://網址/圖片檔.jpg"];

img =[UIImage imageWithData:[NSData dataWithContentsOfURL:url]];

網路傳輸完之後再執行這個 thread

[NSThread detachNewThreadSelector: @selector(actIndicatorEnd) toTarget:self withObject:nil];

再加上這兩個 method 開關旋轉狀態

- (void) actIndicatorBegin {

[activityIndicator startAnimating];

}

-(void) actIndicatorEnd {

[activityIndicator stopAnimating];

}

Source: http://ipdevelop.blogspot.com/2010/10/uiactivityindicatorview.html