java - 当没有可用连接时显示 toast 错误并阻止显示 webview

Question

当没有可用连接时，它会显示默认的浏览器错误页面，我们想要的只是不显示任何浏览器错误页面，而是显示一条 toast 消息和一个空白屏幕。

我的代码:

public class EarnFragment extends Fragment {
WebView mWebView;


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View v=inflater.inflate(R.layout.fragment_earn, container, false);
    mWebView = (WebView) v.findViewById(R.id.webview);
    mWebView.loadUrl("https://demo.hazzardweb.com/easylogin-pro/");

    // Enable Javascript
    WebSettings webSettings = mWebView.getSettings();
    webSettings.setJavaScriptEnabled(true);

    // Force links and redirects to open in the WebView instead of in a browser
    mWebView.setWebViewClient(new WebViewClient());

    return v;
}

}

Answer 1

如果你想显示黑屏而不是网页 View ，首先你需要更改你的布局文件。然后在加载网址之前检查互联网连接。检查互联网连接是否不可用，此时隐藏您的 WebView 并显示您的 Toast 消息和相关布局。否则隐藏Relativelayout noConnection。

第 1 步:创建这样的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <WebView
        android:id="@+id/webViewData"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

    <RelativeLayout
        android:id="@+id/noConnection"
        android:layout_width="match_parent"
        android:background="#000000"
        android:layout_height="match_parent"/>
</RelativeLayout>

</LinearLayout>

第 2 步:使用此功能检查您的互联网连接。

public static boolean checkInternetConnection(Context context) {
    if (context != null) {
        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (cm != null) {
            return cm.getActiveNetworkInfo() != null && cm.getActiveNetworkInfo().isAvailable() && cm.getActiveNetworkInfo().isConnected() && cm.getActiveNetworkInfo().isConnectedOrConnecting();
        } else {
            return false;
        }
    } else {
        return false;
    }

}

最后在加载您的网址之前在代码中执行此操作，

public class EarnFragment extends Fragment {
WebView mWebView;
RelativeLayout noConnection;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                     Bundle savedInstanceState) {

View v=inflater.inflate(R.layout.fragment_earn, container, false);
mWebView = (WebView) v.findViewById(R.id.webview);
noConnection = (RelativeLayout)v.findViewById(R.id.noConnection);

// Enable Javascript
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);

if(checkInternetConnection(getActivity())){
 noConnection.setVisibility(View.GONE);
 mWebView.setVisibility(View.VISIBLE);
 mWebView.loadUrl("https://demo.hazzardweb.com/easylogin-pro/");

}else{
 noConnection.setVisibility(View.VISIBLE);
 mWebView.setVisibility(View.GONE);
}


// Force links and redirects to open in the WebView instead of in a browser
mWebView.setWebViewClient(new WebViewClient());

return v;
}