Android-强大的WebView

可以做哪些事情？

• 加载线上 url

  mWebView.loadUrl("https://www.baidu.com");
  

• 加载本地 html

• 和 js 进行交互

  • js调用原生 App

        public class TestJSEvent {
            @JavascriptInterface // 4.2以上必须加此注解，否则不生效
            public void showToast(String toast) {
                Toast.makeText(WebViewActivity.this, toast, Toast.LENGTH_SHORT).show();
            }
        }
    
    // js调用原生 App
    mWebView.addJavascriptInterface(new TestJSEvent(), "TestApp");
    

  • 原生 App调用 js

    mWebView.loadUrl("javascript:javaCallJS('可以传参数')");
    

• 历史记录

  	WebBackForwardList webBackForwardList = mWebView.copyBackForwardList();
    WebHistoryItem historyItem = webBackForwardList.getItemAtIndex(0);
  	String historyUrl = historyItem.getUrl();
  

• 导航

  @Override
  public void onBackPressed() {
      // 页面回退，而不直接关闭 Activity
      if (mWebView != null && mWebView.canGoBack()) {
         	mWebView.goBack(); // 回退
  		// mWebView.goForward(); // 前进
  		// mWebView.goBackOrForward(+1); // 回退或前进。steps: 负为回退，正为前进
  		// mWebView.reload(); // 刷新
     } else {
        super.onBackPressed();
     }
  }
  

如何使用？

• 申请网络权限

  <!-- 声明使用网络的权限 -->
  <uses-permission android:name="android.permission.INTERNET"/>
  

• 类结构

• 常用设置

  • WebSettings

    // 打开 JavaScript
     mWebView.getSettings().setJavaScriptEnabled(true);
    

  • WebViewClient

    mWebView.setWebViewClient(new WebViewClient() {
    
          @Override
          public boolean shouldOverrideUrlLoading(WebView view, String url) {
               // 是否重新加载（拦截页面）
               return super.shouldOverrideUrlLoading(view, url);
          }
    
          @Override
          public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
                return super.shouldOverrideUrlLoading(view, request);
          }
    
          @Override
          public void onPageStarted(WebView view, String url, Bitmap favicon) {
                // 页面开始加载
    			super.onPageStarted(view, url, favicon);
          }
    
          @Override
          public void onPageFinished(WebView view, String url) {
                // 页面结束
    			super.onPageFinished(view, url);
          }
    
           @Override
           public void onLoadResource(WebView view, String url) {
                // 加载资源
    			super.onLoadResource(view, url);
           }
    
           @Override
           public void onPageCommitVisible(WebView view, String url) {
                super.onPageCommitVisible(view, url);
           }
    
           @Nullable
           @Override
           public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
                // 拦截请求
                return super.shouldInterceptRequest(view, request);
           }
    
           @Override
           public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                // 加载失败时
    			super.onReceivedError(view, errorCode, description, failingUrl);
           }
    });
    

    方法太多了，这里看几个比较常用的

  • WebChromeClient

    mWebView.setWebChromeClient(new WebChromeClient() {
           @Override
           public void onProgressChanged(WebView view, int newProgress) {
                // 获取网页加载的进度
                super.onProgressChanged(view, newProgress);
           }
    
           @Override
           public void onReceivedTitle(WebView view, String title) {
                // 获取网页的标题
                super.onReceivedTitle(view, title);
           }
    
    		@Override
            public void onCloseWindow(WebView window) {
                // 关闭窗口
                super.onCloseWindow(window);
            }
    
            @Override
            public boolean onJsPrompt(WebView view, String url, String message, String defaultValue, JsPromptResult result) {
                // js加载的时候
                return super.onJsPrompt(view, url, message, defaultValue, result);
            }
    
            @Override
            public boolean onJsBeforeUnload(WebView view, String url, String message, JsResult result) {
                // js导入的时候
                return super.onJsBeforeUnload(view, url, message, result);
            }
    
    		@Override
            public void onGeolocationPermissionsShowPrompt(String origin, GeolocationPermissions.Callback callback) {
                // 位置权限
                super.onGeolocationPermissionsShowPrompt(origin, callback);
            }
    });
    

    方法太多了，这里看几个比较常用的

更深入的使用

• Cookie

  CookieManager cookieManager = CookieManager.getInstance();
  cookieManager.setAcceptCookie(true);
  cookieManager.setCookie("domain", "cookie");
  cookieManager.removeAllCookies();
  

• History

  WebBackForwardList webBackForwardList = mWebView.copyBackForwardList();
  WebHistoryItem historyItem = webBackForwardList.getItemAtIndex(0);
  String historyUrl = historyItem.getUrl();
  

• 页面导航

• Hybird

  Hybrid App（混合模式移动应用）是指介于 Web App（套壳）、Native App（原生）这两者之间的 App ，兼具“ Native App 良好用户交互体验的优势 ”和“ Web App 跨平台开发的优势 ”。

• 如何拦截网络请求

  @Nullable
  @Override
   public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
      // 拦截请求
      return super.shouldInterceptRequest(view, request);
  }
  

• 如何显示进度

  @Override
  public void onProgressChanged(WebView view, int newProgress) {
      // 获取网页加载的进度
      super.onProgressChanged(view, newProgress);
  }
  

• 调试

  WebView.setWebContentsDebuggingEnabled(true);