這篇文章主要是 講一些 UIWebView的簡(jiǎn)單知識(shí)，實(shí)現(xiàn)一個(gè)瀏覽器的效果和加載文件（txt，html，pdf等）

關(guān)于MIMIE Type

就是服務(wù)器告訴瀏覽器發(fā)送的多媒體數(shù)據(jù)的類型。（更多請(qǐng)自行Google）
MIME類型能包括視頻、圖像、文本、音頻、應(yīng)用程序等。

獲取指定URL的MIME類型

#pragma mark - 獲取指定URL的MIME type 類型
- (NSString *)mimeType:(NSURL *)url
{
    //1.NSURLRequest
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    //2.NSURLConnection
    //從NSURLResponse 可以獲取服務(wù)器返回的MIMEType
    //使用同步方法獲取MIME
    NSURLResponse *response = nil;
    [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
     return response.MIMEType;
}

加載沙盒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];
   
}

加載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];
    
}

加載文本文件

- (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];
    
}

記載PDF.png

一個(gè)瀏覽器的例子

實(shí)現(xiàn)前進(jìn)、后退、刷新

頂部的文本框、前進(jìn)、后退、刷新 UI

UIToolbar *toolbar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 20, 320, 44)];
    [self.view addSubview:toolbar];
    //1>.1個(gè)textField (textField 以自定義視圖的形式加入到toolbar)
    UITextField *textfield = [[UITextField alloc]initWithFrame:CGRectMake(10, 26, 200, 32)];
    //設(shè)置邊框、設(shè)置對(duì)其、設(shè)置清楚按鈕
    [textfield setBorderStyle:UITextBorderStyleRoundedRect];
    [textfield setContentVerticalAlignment:UIControlContentVerticalAlignmentCenter];
    [textfield setClearButtonMode:UITextFieldViewModeWhileEditing];
    [textfield setDelegate:self];
    UIBarButtonItem *addressItem = [[UIBarButtonItem alloc]initWithCustomView:textfield];
    //2>.三個(gè)按鈕
    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)];
    
    //將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];

文本框回車時(shí)關(guān)閉鍵盤 開始請(qǐng)求

首先遵守協(xié)議：<UITextFieldDelegate>

- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    //1.關(guān)閉鍵盤
    [textField resignFirstResponder];
    //2.讓webview加載地址欄中的內(nèi)容,如果沒有內(nèi)容不加載
    //關(guān)于字符串的比較  是屬于消耗性能的 在判斷是否有內(nèi)容時(shí)，可以使用長度是否為0
    if(textField.text.length > 0){
        [self loadContentWithURLString:textField.text];
    }
    return YES;
}

根據(jù)類型 分流請(qǐng)求

- (void)loadContentWithURLString:(NSString *)urlString
{
    BOOL hasError = NO;
    //針對(duì)urlStrig進(jìn)行判斷
    //1.如果是http開頭說明是web地址
    if([urlString hasPrefix:@"http://"]){
        [self loadURL:[NSURL URLWithString:urlString]];
    }else if ([urlString hasPrefix:@"file://"]){
        //2.如果是file開頭說明是加載沙箱的文件       
    }else{
        hasError = YES;
    }
    if (hasError == YES) {
        UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"提示" message:@"地址錯(cuò)誤" delegate:nil cancelButtonTitle:@"確定" otherButtonTitles:nil, nil];
        [alertView show];
        
    }
}

發(fā)起http請(qǐng)求

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

前進(jìn)后退刷新

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

瀏覽器.png

做個(gè)筆記，一步一步，一起學(xué)習(xí)......