IOS开发网络基础02UIWebView

这篇文章主要是 讲一些 UIWebView的简单知识，实现一个浏览器的效果和加载文件（txt，html，pdf等）

关于MIMIE Type

就是服务器告诉浏览器发送的多媒体数据的类型。（更多请自行Google）
MIME类型能包括视频、图像、文本、音频、应用程序等。

获取指定URL的MIME类型

#pragma mark - 获取指定URL的MIME type 类型
- (NSString *)mimeType:(NSURL *)url
{
    //1.NSURLRequest
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    //2.NSURLConnection
    //从NSURLResponse 可以获取服务器返回的MIMEType
    //使用同步方法获取MIME
    NSURLResponse *response = nil;
    [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
     return response.MIMEType;
}

加载沙盒html文件

- (void)loadHtml
{
    
    NSString *path = [[NSBundle mainBundle]pathForResource:@"1.html" ofType:nil];
    NSURL *url = [NSURL fileURLWithPath:path];
    NSLog(@"%@",[self mimeType:url]);
    
    NSData *data = [NSData dataWithContentsOfFile:path];
    [self.webView loadData:data MIMEType:@"text/html" textEncodingName:@"UFT-8" baseURL:nil];
   
}

加载PDF文件

- (void)loadPDF
{
    NSString *path = [[NSBundle mainBundle]pathForResource:@"1.pdf" ofType:nil];
    NSURL *url = [NSURL fileURLWithPath:path];
    NSLog(@"%@",[self mimeType:url]);
    NSData *data = [NSData dataWithContentsOfFile:path];
    [self.webView loadData:data MIMEType:@"application/pdf" textEncodingName:@"UFT-8" baseURL:nil];
    
}

加载文本文件

- (void)loadTxt
{
    NSString *path = [[NSBundle mainBundle]pathForResource:@"1.txt" ofType:nil];
    NSURL *url = [NSURL fileURLWithPath:path];
    NSLog(@"%@",[self mimeType:url]);
    NSData *data = [NSData dataWithContentsOfFile:path];
    [self.webView loadData:data MIMEType:@"text/plain" textEncodingName:@"UFT-8" baseURL:nil];
    
}

记载PDF.png

一个浏览器的例子

实现前进、后退、刷新

顶部的文本框、前进、后退、刷新 UI

UIToolbar *toolbar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 20, 320, 44)];
    [self.view addSubview:toolbar];
    //1>.1个textField (textField 以自定义视图的形式加入到toolbar)
    UITextField *textfield = [[UITextField alloc]initWithFrame:CGRectMake(10, 26, 200, 32)];
    //设置边框、设置对其、设置清楚按钮
    [textfield setBorderStyle:UITextBorderStyleRoundedRect];
    [textfield setContentVerticalAlignment:UIControlContentVerticalAlignmentCenter];
    [textfield setClearButtonMode:UITextFieldViewModeWhileEditing];
    [textfield setDelegate:self];
    UIBarButtonItem *addressItem = [[UIBarButtonItem alloc]initWithCustomView:textfield];
    //2>.三个按钮
    UIBarButtonItem *item1 = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemRewind target:self action:@selector(goBack)];
    UIBarButtonItem *item2 = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFastForward target:self action:@selector(goForward)];
    UIBarButtonItem *item3 = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refresh)];
    
    //将UIBarButtonItem加入boolbar
    [toolbar setItems:@[addressItem,item1,item2,item3]];
    //2.UIWebView
    UIWebView *webView = [[UIWebView alloc]initWithFrame:CGRectMake(0, 64, 320, self.view.bounds.size.height - 64)];
    [self.view addSubview:webView];

文本框回车时关闭键盘 开始请求

首先遵守协议：<UITextFieldDelegate>

- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    //1.关闭键盘
    [textField resignFirstResponder];
    //2.让webview加载地址栏中的内容,如果没有内容不加载
    //关于字符串的比较  是属于消耗性能的 在判断是否有内容时，可以使用长度是否为0
    if(textField.text.length > 0){
        [self loadContentWithURLString:textField.text];
    }
    return YES;
}

根据类型 分流请求

- (void)loadContentWithURLString:(NSString *)urlString
{
    BOOL hasError = NO;
    //针对urlStrig进行判断
    //1.如果是http开头说明是web地址
    if([urlString hasPrefix:@"http://"]){
        [self loadURL:[NSURL URLWithString:urlString]];
    }else if ([urlString hasPrefix:@"file://"]){
        //2.如果是file开头说明是加载沙箱的文件       
    }else{
        hasError = YES;
    }
    if (hasError == YES) {
        UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"提示" message:@"地址错误" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
        [alertView show];
        
    }
}

发起http请求

- (void)loadURL:(NSURL *)url
{
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [self.webView loadRequest:request];
}

前进后退刷新

#pragma mark 后对
- (void)goBack
{
    [self.webView goBack];
    NSLog(@"后退");
}
#pragma mark 前进
- (void)goForward
{
    [self.webView goForward];
    NSLog(@"前进");
}
#pragma mark 刷新
- (void)refresh
{
    [self.webView reload];
    NSLog(@"刷新");
}

浏览器.png

做个笔记，一步一步，一起学习......