Back按鈕在WebView中無法按預期工作 - Android

Question

我有4個片段，使用view-pager和tabs在主要活動中顯示新聞。但是我的代碼僅適用於第一個片段，即標籤1

在主要活動中，我有

@Override 
    public void onBackPressed() { 

     WebView mWebView = (WebView) findViewById(R.id.webview); 
     if (mWebView.getVisibility() == View.VISIBLE) { 
      mWebView.setVisibility(View.GONE); 
      mWebView.loadUrl("about:blank"); 
     } 
     else { 

      super.onBackPressed(); 
     } 

     return; 
    } 

當按下後退按鈕，它通過採取用戶返回到主佈局隱藏web視圖那裏。它適用於選項卡1

但在片段2,3,4 - 當我按回按鈕退出應用程序。我使用相同的代碼作爲片段1

我發現 - mWebView.getVisibility（）== View.VISIBLE沒有得到真正的 - 即使在網絡視圖是碎片2,3,4

可見

片段1個代碼：

public class WSJFragment extends Fragment implements LoaderManager.LoaderCallbacks<List<News>> { 


    ......... 


    public WSJFragment() { 
     // Required empty public constructor 
    } 


    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     rootView = inflater.inflate(R.layout.newsview, container, false); 

     ............ 

     NewsListView.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
      @Override 
      public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) { 
       // Find the current earthquake that was clicked on 
       News currentNews = mAdapter.getItem(position); 


       String newsUrl = currentNews.getUrl(); 

       progress.setVisibility(View.VISIBLE); 

       mWebView.setVisibility(View.VISIBLE); 

       mWebView.loadUrl(newsUrl); 

       mWebView.setWebViewClient(new WebViewClient() { 
        @Override 
        public void onPageFinished(WebView view, String url) { 
         super.onPageFinished(mWebView, url); 
         progress.setVisibility(View.GONE); 

        } 

       }); 


      } 


     }); 


     return rootView; 
    } 


    ........ 

} 

https://github.com/mrafz/W3News

Answer 1

我已經在你的代碼進行覈對，使這一變化。

在MainActivity與此

@Override 
public void onBackPressed() { 

    if(mWebView != null){ 
     if (mWebView.getVisibility() == View.VISIBLE) { 
      mWebView.setVisibility(View.GONE); 
      mWebView.loadUrl("about:blank"); 
     }else { 
      finish(); 
     } 
    }else{ //if webview is null do something... here 
    } 
} 

在所有4個片段代替本

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    rootView = inflater.inflate(R.layout.newsview, container, false); 

    MainActivity.mWebView = (WebView) rootView.findViewById(R.id.webview); 
    MainActivity.mWebView.setVisibility(View.GONE); 

    //your remaining code here 

return rootView; 
} 

並且在任何你找到「mWebView」對象替換每個片段取代它與MainActivity.mWebView