逐帧动画做loading视图

我封装了一个可复用的loading视图组件，用于按照一定周期逐帧播放加载动画。代码如下：

.h文件

#import <UIKit/UIKit.h>//加载状态typedef enum {    FZImageSequenceLoadingStatusStop = 1,          // 停止    FZImageSequenceLoadingStatusLoading,         // 加载中    FZImageSequenceLoadingStatusError   //发生错误} FZImageSequenceLoadingStatus;@interface FZImageSequenceLoadingView : UIView {    UIImageView *_imageView;    UILabel *_lblMsg;    NSTimer *timer;    int currentImageIndex;}@property(strong) NSArray *imageArray;  //动画序列的图片数组@property(strong, nonatomic) UIImage *errorImage;@property(nonatomic, strong) NSString *errorMsg;@property(nonatomic, strong) NSString *loadingMsg; //提示文字@property(nonatomic) CGRect imageFrame; //图片的Frame@property(nonatomic) CGRect msgFrame;   //文字内容的Frame@property(nonatomic) float timerInterval; //切换图片的周期/** 切换状态 */- (void)switchToStatus:(FZImageSequenceLoadingStatus)status;/** 通过图片名字和数量设置图片数组，如给定名字"name"、“.png”和数量4，则会去加载“name_1.png”到"name_4.png"的图片 */- (void)setImageArrayByName:(NSString *)name andExtName:(NSString *)extName andCount:(int)count;@end

.m文件

#import "FZImageSequenceLoadingView.h"@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 {//    self.backgroundColor = [UIColor redColor];    if (self.imageArray && self.imageArray.count > 0) {        if (!_imageView) {            _imageView = [[UIImageView alloc] init];            [self addSubview:_imageView];        }        //让图片view为本view的顶部居中，大小为图片数组中的第一张        UIImage *firstImg = [self.imageArray objectAtIndex:0];        _imageView.size = firstImg.size;        _imageView.top = 0;        _imageView.left = (self.size.width - _imageView.size.width) / 2;    }            if (self.loadingMsg) {        CGSize labelSize = [self.loadingMsg 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 = self.height;        _lblMsg.left = (self.width - _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 (self.imageArray && self.imageArray.count > 0) {        _imageView.image = [self.imageArray objectAtIndex:0];    }}- (void)switchToError {    [timer invalidate];    timer = nil;    //如果有错误状态的图    if (self.errorImage) {        _imageView.image = self.errorImage;        //如果没有就用第一张动画图    } else if (self.imageArray && self.imageArray.count > 0) {        _imageView.image = [self.imageArray objectAtIndex:0];    }        if (self.errorMsg) {        _lblMsg.text = self.errorMsg;    }}- (void)switchToLoading {    if (self.loadingMsg) {        _lblMsg.text = self.loadingMsg;    }    if (!timer) {        timer = [NSTimer scheduledTimerWithTimeInterval:self.timerInterval target:self selector:@selector(showNextImage) userInfo:nil repeats:YES];    }}- (void)showNextImage {    if (!imageArray || imageArray.count < 1) {        return;    }    currentImageIndex = (currentImageIndex + 1) % self.imageArray.count;    // 主线程执行：    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)), @"图片名字和数量错误");    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];    }    self.imageArray = imgs;}@end

使用示例，在uiwebview中使用如下：

初始化视图：

//设置loading视图- (void)setupLoadingView {    if (!_loadingView) {        _loadingView = [[FZImageSequenceLoadingView alloc] initWithFrame:CGRectMake(0, 0, 170, 70)];        _loadingView.center = self.view.center;        [_loadingView setImageArrayByName:@"loading" andExtName:@".png" andCount:10];        _loadingView.loadingMsg = @"努力加载中，请稍候";        _loadingView.errorMsg = @"加载失败";        _loadingView.timerInterval = 0.1;        _loadingView.hidden = YES;        [self.view addSubview:_loadingView];    }}

在uiwebview的代理方法中切换状态：

#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];    }}

目前该组件功能还不够完善，但是能满足目前我自己的需求，后续再继续丰富。