//
//  OpenWebViewController.m
//  Treasure
//
//  Created by 藍藍色信子 on 16/7/29.
//  Copyright ? 2016年 GY. All rights reserved.
//

#import "ZTOpenWebViewController.h"
#import <WebKit/WebKit.h>

@interface ZTOpenWebViewController ()<WKNavigationDelegate>
//{
//    //網頁視圖
//    UIWebView * _webView;
//}
@property (strong, nonatomic) WKWebView *webView;


@property (strong, nonatomic) UIProgressView 
 
*progressView;

@end

@implementation ZTOpenWebViewController



- (void)viewDidLoad {
    [super viewDidLoad];
    //    //取消導航欄的影響
    self.automaticallyAdjustsScrollViewInsets = NO;
    self.view.backgroundColor = [UIColor whiteColor];
    
    //[SVProgressHUD show];
    //實例化
    [self createWebView];
    
    [self creatCustomProgressView];
}

 
-(void)creatCustomProgressView{
    
    //增加加載進度條
    // KVO，監聽webView屬性值得變化(estimatedProgress,title為特定的key)
    [_webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:nil];
    [_webView addObserver:self forKeyPath:@"title" options:NSKeyValueObservingOptionNew context:nil];
    
    
 
// UIProgressView初始化
    self.progressView = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleDefault];
    self.progressView.frame = CGRectMake(0, 0, _webView.frame.size.width, 5);
    self.progressView.trackTintColor = [UIColor clearColor]; // 設置進度條的色彩
    self.progressView.progressTintColor = [UIColor magentaColor];
    // 設置初始的進度，防止用戶進來就懵逼了（微信大概也是一開始設置的10%的默認值）
    [self.progressView setProgress:0.1 animated:YES];
    [_webView addSubview:self.progressView];
}

- (void)viewWillAppear:(BOOL)animated
{
    [self.navigationController setNavigationBarHidden:NO animated:NO];
    [super viewWillAppear:YES];
}
- (void)viewWillDisappear:(BOOL)animated
{
    [SVProgressHUD dismiss];
    [super viewWillDisappear:animated];
}

- (void)createWebView
{
    _webView = [[WKWebView alloc]initWithFrame:self.view.bounds];
    
    [self.view addSubview:_webView];
    
    //調整適應比例
    //_webView.scalesPageToFit = YES;
    //設置代理
    _webView.navigationDelegate = self;
    [[NSURLCache sharedURLCache] removeAllCachedResponses];
    [_webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:self.urlStr] cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData timeoutInterval:10.0]];
    
}
#pragma mark - WKWebView NavigationDelegate

//WKNavigationDelegate
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
    //NSLog(@"是否允許這個導航");
    decisionHandler(WKNavigationActionPolicyAllow);
}

- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler {
    //    Decides whether to allow or cancel a navigation after its response is known.
    
    //NSLog(@"知道返回內容之後，是否允許加載，允許加載");
    decisionHandler(WKNavigationResponsePolicyAllow);
}
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(null_unspecified WKNavigation *)navigation {
    //NSLog(@"開始加載");
    //self.progress.alpha  = 1;
    
    //[SVProgressHUD show];
    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    
}

- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(null_unspecified WKNavigation *)navigation {
    //NSLog(@"跳轉到其他的服務器");
    
}

- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(null_unspecified WKNavigation *)navigation withError:(NSError *)error {
    //NSLog(@"網頁由於某些原因加載失敗");
    //[SVProgressHUD dismiss];
    //self.progress.alpha  = 0;
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
- (void)webView:(WKWebView *)webView didCommitNavigation:(null_unspecified WKNavigation *)navigation {
    //NSLog(@"網頁開始接收網頁內容");
}
- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation {
    //NSLog(@"網頁導航加載完畢");
    //[SVProgressHUD dismiss];
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    
    self.title = webView.title;
    [webView evaluateJavaScript:@"document.title" completionHandler:^(id _Nullable ss, NSError * _Nullable error) {
        //NSLog(@"----document.title:%@---webView title:%@",ss,webView.title);
    }];
    //self.progress.alpha  = 0;
    
}

- (void)webView:(WKWebView *)webView didFailNavigation:(null_unspecified WKNavigation *)navigation withError:(NSError *)error {
    //NSLog(@"加載失敗,失敗原因:%@",[error description]);
    //self.progress.alpha = 0;
}
- (void)webViewWebContentProcessDidTerminate:(WKWebView *)webView {
    //NSLog(@"網頁加載內容進程終止");
}


#pragma mark - KVO監聽
// 第三部：完成監聽方法
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    
    if ([object isEqual:_webView] && [keyPath isEqualToString:@"estimatedProgress"]) { // 進度條
        
        CGFloat newprogress = [[change objectForKey:NSKeyValueChangeNewKey] doubleValue];
        //NSLog(@"打印測試進度值：%f", newprogress);
        
        if (newprogress == 1) { // 加載完成
            // 首先加載到頭
            [self.progressView setProgress:newprogress animated:YES];
            // 之後0.3秒延遲隱藏
            __weak typeof(self) weakSelf = self;
            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 0.3 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
                
                weakSelf.progressView.hidden = YES;
                [weakSelf.progressView setProgress:0 animated:NO];
            });
            
        } else { // 加載中
            self.progressView.hidden = NO;
            [self.progressView setProgress:newprogress animated:YES];
        }
    } else if ([object isEqual:_webView] && [keyPath isEqualToString:@"title"]) { // 標題
        
        //self.title = _webView.title;
    } else { // 其他
        
        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
    }
}

-(void)dealloc{
    NSLog(@"webVC dealloc = %@",self);
    [_webView removeObserver:self forKeyPath:@"estimatedProgress"];
    [_webView removeObserver:self forKeyPath:@"title"];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
 #pragma mark - Navigation
 
 // In a storyboard-based application, you will often want to do a little preparation before navigation
 - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
 // Get the new view controller using [segue destinationViewController].
 // Pass the selected object to the new view controller.
 }
 */

@end

一個KVO 實現WKWebView加載進度條的例子 （註意最後移除觀察者）