iOS 加载webView进度条

项目demo链接：https://github.com/MinLee6/WebViewLoadProgress

现在的app常常会嵌入不少的h5页面，这里参照微信显示web页面的方式,做了一个导航栏下的加载进度条.因为项目最低支持iOS7,所以不能使用WKWebView来加载网页,只能使用 UIWebView,查看 UIWebView的API可以发现,并没有代理或是通知告诉我们webView加载了多少,所以这个进度条我决定用虚拟的方式来做,就是假装知道加载了多少.

加载WebView的控制器LMWebController




LMWebController.m


////  LMWebController.m//  LMWebViewLoadProgress////  Created by limin on 17/1/16.//  Copyright © 2017年 君安信（北京）科技有限公司. All rights reserved.//#import "LMWebController.h"#import "LMWebProgressLayer.h"#import "UIView+Frame.h"@interface LMWebController ()<UIWebViewDelegate>@end@implementation LMWebController{    UIWebView *_webView;        LMWebProgressLayer *_progressLayer; ///< 网页加载进度条}- (void)viewDidLoad {    [super viewDidLoad];        self.view.backgroundColor = [UIColor whiteColor];    [self setupUI];}- (void)setupUI {    _webView = [[UIWebView alloc] initWithFrame:self.view.bounds];    _webView.delegate = self;    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:self.url]];    [_webView loadRequest:request];        _webView.backgroundColor = [UIColor whiteColor];        _progressLayer = [LMWebProgressLayer new];    _progressLayer.frame = CGRectMake(0, 42, SCREEN_WIDTH, 2);        [self.navigationController.navigationBar.layer addSublayer:_progressLayer];    [self.view addSubview:_webView];}#pragma mark - UIWebViewDelegate- (void)webViewDidStartLoad:(UIWebView *)webView {    [_progressLayer startLoad];}- (void)webViewDidFinishLoad:(UIWebView *)webView {    [_progressLayer finishedLoad];    self.title = [webView stringByEvaluatingJavaScriptFromString:@"document.title"];    }- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {    [_progressLayer finishedLoad];}- (void)dealloc {        [_progressLayer closeTimer];    [_progressLayer removeFromSuperlayer];    _progressLayer = nil;    NSLog(@"i am dealloc");}@end

进度条：LMWebProgressLayer.h

////  LMWebProgressLayer.h//  LMWebViewLoadProgress////  Created by limin on 17/1/16.//  Copyright © 2017年 君安信（北京）科技有限公司. All rights reserved.//#import <QuartzCore/QuartzCore.h>#import <UIKit/UIKit.h>#define SCREEN_WIDTH [UIScreen mainScreen].bounds.size.width@interface LMWebProgressLayer : CAShapeLayer- (void)finishedLoad;- (void)startLoad;- (void)closeTimer;@end

进度条：LMWebProgressLayer.m

////  LMWebProgressLayer.m//  LMWebViewLoadProgress////  Created by limin on 17/1/16.//  Copyright © 2017年 君安信（北京）科技有限公司. All rights reserved.//#import "LMWebProgressLayer.h"#import "NSTimer+Addition.h"static NSTimeInterval const kFastTimeInterval = 0.003;@implementation LMWebProgressLayer{    CAShapeLayer *_layer;        NSTimer *_timer;    CGFloat _plusWidth; ///< 增加点}- (instancetype)init {    if (self = [super init]) {        [self initialize];    }    return self;}- (void)initialize {    self.lineWidth = 2;    self.strokeColor = [UIColor greenColor].CGColor;        _timer = [NSTimer scheduledTimerWithTimeInterval:kFastTimeInterval target:self selector:@selector(pathChanged:) userInfo:nil repeats:YES];    [_timer pause];        UIBezierPath *path = [UIBezierPath bezierPath];    [path moveToPoint:CGPointMake(0, 2)];    [path addLineToPoint:CGPointMake(SCREEN_WIDTH, 2)];        self.path = path.CGPath;    self.strokeEnd = 0;    _plusWidth = 0.01;}- (void)pathChanged:(NSTimer *)timer {    self.strokeEnd += _plusWidth;        if (self.strokeEnd > 0.8) {        _plusWidth = 0.002;    }}- (void)startLoad {    [_timer resumeWithTimeInterval:kFastTimeInterval];}- (void)finishedLoad {    [self closeTimer];        self.strokeEnd = 1.0;    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.25 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{        self.hidden = YES;        [self removeFromSuperlayer];    });}- (void)dealloc {    //    NSLog(@"progressView dealloc");    [self closeTimer];}#pragma mark - private- (void)closeTimer {    [_timer invalidate];    _timer = nil;}@end

定时器:NSTimer+Addition.h

////  NSTimer+Addition.h//  LMWebViewLoadProgress////  Created by limin on 17/1/16.//  Copyright © 2017年 君安信（北京）科技有限公司. All rights reserved.//#import <Foundation/Foundation.h>@interface NSTimer (Addition)- (void)pause;- (void)resume;- (void)resumeWithTimeInterval:(NSTimeInterval)time;@end

定时器:NSTimer+Addition.m

////  NSTimer+Addition.m//  LMWebViewLoadProgress////  Created by limin on 17/1/16.//  Copyright © 2017年 君安信（北京）科技有限公司. All rights reserved.//#import "NSTimer+Addition.h"@implementation NSTimer (Addition)- (void)pause {    if (!self.isValid) return;    [self setFireDate:[NSDate distantFuture]];}- (void)resume {    if (!self.isValid) return;    [self setFireDate:[NSDate date]];}- (void)resumeWithTimeInterval:(NSTimeInterval)time {    if (!self.isValid) return;    [self setFireDate:[NSDate dateWithTimeIntervalSinceNow:time]];}@end