iOS implements frame-by-frame animation to load view

#import <UIKit/>
 
//Loading statustypedef enum {
    FZImageSequenceLoadingStatusStop = 1,          // stop    FZImageSequenceLoadingStatusLoading,         // loading    FZImageSequenceLoadingStatusError   // An error occurred} FZImageSequenceLoadingStatus;
 
@interface FZImageSequenceLoadingView : UIView {
    UIImageView *_imageView;
    UILabel *_lblMsg;
    NSTimer *timer;
    int currentImageIndex;
}
 
@property(strong) NSArray *imageArray;  //Anime sequence picture array 
@property(strong, nonatomic) UIImage *errorImage;
 
@property(nonatomic, strong) NSString *errorMsg;
 
@property(nonatomic, strong) NSString *loadingMsg; // Prompt text 
@property(nonatomic) CGRect imageFrame; //The picture frame 
@property(nonatomic) CGRect msgFrame;   //Frame of text content 
@property(nonatomic) float timerInterval; //Switch the cycle of the picture 
/**
  Switch status
  */
- (void)switchToStatus:(FZImageSequenceLoadingStatus)status;
 
/**
  Setting the image array by image name and quantity, such as given the names "name", ".png" and quantity 4, the image from "name_1.png" to "name_4.png" will be loaded.
  */
- (void)setImageArrayByName:(NSString *)name andExtName:(NSString *)extName andCount:(int)count;
 
@end

#import ""
 
@implementation FZImageSequenceLoadingView
 
@synthesize errorImage;
@synthesize errorMsg;
@synthesize imageArray;
@synthesize loadingMsg;
@synthesize timerInterval;
 
- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        timerInterval = 1;
        currentImageIndex = -1;
    }
    return self;
}
 
/*
 // Only override drawRect: if you perform custom drawing.
 // An empty implementation adversely affects performance during animation.
 - (void)drawRect:(CGRect)rect
 {
 // Drawing code
 }
 */
 
- (void)setupSubviews {
//     = [UIColor redColor];
    if ( &&  > 0) {
        if (!_imageView) {
            _imageView = [[UIImageView alloc] init];
            [self addSubview:_imageView];
        }
        //Let the image view be the top of the view centered, and the size is the first picture in the image array        UIImage *firstImg = [ objectAtIndex:0];
        _imageView.size = ;
        _imageView.top = 0;
        _imageView.left = ( - _imageView.) / 2;
    }
    
    
    if () {
        CGSize labelSize = [ sizeWithFont:[UIFont systemFontOfSize:11]];
        if (!_lblMsg) {
            _lblMsg = [[UILabel alloc] initWithFrame:CGRectZero];
            _lblMsg.textAlignment = NSTextAlignmentCenter;
            [self addSubview:_lblMsg];
        }
        _lblMsg.font = [UIFont systemFontOfSize:11];
        _lblMsg.size = labelSize;
        _lblMsg.textColor = [UIColor darkGrayColor];
        _lblMsg.backgroundColor = [UIColor clearColor];
        _lblMsg.bottom = ;
        _lblMsg.left = ( - _lblMsg.width) / 2;
    }
}
 
- (void)switchToStatus:(FZImageSequenceLoadingStatus)status {
    if (!_lblMsg || !_imageView) {
        [self setupSubviews];
    }
    switch (status) {
        case FZImageSequenceLoadingStatusError:
            [self switchToError];
            break;
        case FZImageSequenceLoadingStatusLoading:
            [self switchToLoading];
            break;
        case FZImageSequenceLoadingStatusStop:
            [self switchToStop];
            break;
    }
}
 
- (void)switchToStop {
    [timer invalidate];
    timer = nil;
    if ( &&  > 0) {
        _imageView.image = [ objectAtIndex:0];
    }
}
 
- (void)switchToError {
    [timer invalidate];
    timer = nil;
    // If there is an error state diagram    if () {
        _imageView.image = ;
        //If not, use the first animation picture    } else if ( &&  > 0) {
        _imageView.image = [ objectAtIndex:0];
    }
    
    if () {
        _lblMsg.text = ;
    }
}
 
- (void)switchToLoading {
    if () {
        _lblMsg.text = ;
    }
    if (!timer) {
        timer = [NSTimer scheduledTimerWithTimeInterval: target:self selector:@selector(showNextImage) userInfo:nil repeats:YES];
    }
}
 
- (void)showNextImage {
    if (!imageArray ||  < 1) {
        return;
    }
    currentImageIndex = (currentImageIndex + 1) % ;
    // Main thread execution:    dispatch_async(dispatch_get_main_queue(), ^{
        _imageView.image = [imageArray objectAtIndex:currentImageIndex];
    });
}
 
- (void)setImageArrayByName:(NSString *)name andExtName:(NSString *)extName andCount:(int)count {
    NSAssert((name && extName && (count > 0)), @"Image name and quantity");
    NSMutableArray *imgs = [NSMutableArray arrayWithCapacity:count];
    for (int i = 1; i <= count; i++) {
        NSString *imgName = [NSString stringWithFormat:@"%@_%i%@", name, i, extName];
        UIImage *image = [UIImage imageNamed:imgName];
        NSLog(@"%@", image);
        if (!image) {
            continue;
        }
        [imgs addObject:image];
    }
     = imgs;
}
 
@end

//Set loading view- (void)setupLoadingView {
    if (!_loadingView) {
        _loadingView = [[FZImageSequenceLoadingView alloc] initWithFrame:CGRectMake(0, 0, 170, 70)];
        _loadingView.center = ;
        [_loadingView setImageArrayByName:@"loading" andExtName:@".png" andCount:10];
        _loadingView.loadingMsg = @"Please wait";
        _loadingView.errorMsg = @"Loading failed";
        _loadingView.timerInterval = 0.1;
        _loadingView.hidden = YES;
        [ addSubview:_loadingView];
    }
}

#pragma mark - webview delegate
- (void)webViewDidStartLoad:(UIWebView *)webView {
    if (_loadingView.hidden) {
        _loadingView.hidden = NO;
        [_loadingView switchToStatus:FZImageSequenceLoadingStatusLoading];        
    }
}
 
- (void)webViewDidFinishLoad:(UIWebView *)webView {
    if (!_loadingView.hidden) {
        [_loadingView switchToStatus:FZImageSequenceLoadingStatusStop];
        _loadingView.hidden = YES;
    }
    
}
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
    NSLog(@"load page error:%@", [error description]);
    if (!_loadingView.hidden) {
        [_loadingView switchToStatus:FZImageSequenceLoadingStatusError];
    }
}