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我想我应该首先说我对 eclipse 和 java 完全陌生。我正在尝试使用启动我的网页的 eclipse 创建一个 android 应用程序。我有一个运行良好的代码示例，但它几乎是从我在网上找到的示例中复制和粘贴的，所以请原谅我草率的代码。我想知道如何检查 Internet 或 wifi 连接是否可用。如果没有连接，则显示警报（没有 Internet 连接）。我发现了一些类似的问题，但我只是不确定在哪里放置代码？有人可以告诉我吗？

    package com.mysite.news;

    import com.mysite.news.R;
    import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.Window;

import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;




public class WebActivity extends Activity {

    private WebView wv;

    private String LASTURL = "";

    Menu myMenu = null;

    private static final String PREFS_NAME = "MyPrefs";



    private Boolean imgOn;

    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate( Bundle savedInstanceState ) {
        super.onCreate( savedInstanceState );
        this.getWindow().requestFeature( Window.FEATURE_PROGRESS );
        setContentView( R.layout.web_view );

        wv = ( WebView ) findViewById( R.id.web_view );

        WebSettings webSettings = wv.getSettings();
        webSettings.setSavePassword( true );
        webSettings.setSaveFormData( true );
        webSettings.setJavaScriptEnabled( true );
        webSettings.setUseWideViewPort(true);
        webSettings.setLoadWithOverviewMode(true);
        webSettings.setSupportZoom(false);


        SharedPreferences settings = getSharedPreferences( PREFS_NAME, 0 );
        imgOn = settings.getBoolean( "IMGMODE", false );
        webSettings.setLoadsImagesAutomatically( imgOn );

        final Activity activity = this;


        // start ProgressDialog with "Page loading..."
        final ProgressDialog dialog = new ProgressDialog( activity );
        dialog.setMessage( "Page loading..." );
        dialog.setIndeterminate( true );
        dialog.setCancelable( true );
        dialog.show();

        wv.setWebChromeClient( new WebChromeClient() {
            public void onProgressChanged( WebView view, int progress ) {
                // set address bar and progress
//              activity.setTitle( " " + LASTURL );
//              activity.setProgress( progress * 100 );

                if( progress == 100 ) {
                    // stop ProgressDialog after loading
                    dialog.dismiss();

//                  activity.setTitle( " " + LASTURL );
                }
            }
        } );

        wv.setWebViewClient( new WebViewClient() {
            public void onReceivedError( WebView view, int errorCode, String description, String failingUrl ) {
                Toast.makeText( getApplicationContext(), "Error: " + description + " " + failingUrl, Toast.LENGTH_LONG ).show();
            }

            @Override
            public boolean shouldOverrideUrlLoading( WebView view, String url ) {
                if( url.indexOf( "mysite" ) <= 0 ) {
                    // the link is not for a page on my site, so launch another Activity that handles URLs
                    Intent intent = new Intent( Intent.ACTION_VIEW, Uri.parse( url ) );
                    startActivity( intent );
                    return true;
                }
                return false;
            }

            public void onPageStarted( WebView view, String url, Bitmap favicon ) {
                LASTURL = url;
                view.getSettings().setLoadsImagesAutomatically( true );
                view.getSettings().setBuiltInZoomControls( true );
            }

            public void onPageFinished( WebView view, String url ) {
                view.loadUrl( "javascript:(function() { " +
                                      "hide('sidebar');" +
                                      //"var parent = document.getElementsByClassName('page-navigation')[0];"+
                                      //"var panel = document.getElementsByClassName('panel-tools')[0];"+
                                      //"var div = document.createElement('div');"+
                                      //"div.innerHTML = panel.innerHTML;"+
                                      //"parent.appendChild(div);"+
                                      //"panel.innerHTML = '';"+
                                      //"div.style['margin-left'] = '31px';"+
                                      "var panel = document.getElementById('search');" +
                                      "panel.style['width'] = '55px';" +

                                      //"var imgs=document.getElementsByTagName('IMG');for(var i=0;i<imgs.length;i++){if (imgs[i].height=60) {imgs[i].src='';imgs[i].width=0;} }"+
                                      //"var urls=document.getElementsByTagName('li');for(var i=0;i<urls.length;i++){if (urls[i].style='margin: -14px 0pt 0pt;'){urls[i].style['display'] = 'none';}}"+
                                      //"hideByClass('panel-tools');"+
                                      "function hide(id){if (document.getElementById(id)){document.getElementById(id).style['display'] = 'none';}}" +
                                      //"function hideByClass(c){var e=document.getElementsByClassName(c);for(var i=0;i<e.length;i++){e[i].style['display'] = 'none';}}"+
                                      "})()" );
                if( imgOn ) {
                    view.getSettings().setLoadsImagesAutomatically( true );
                    view.getSettings().setSupportZoom(false);

                }
            }
        } );
        wv.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
        wv.setScrollbarFadingEnabled(false);
        wv.loadUrl( "http://www.mysite.com" );
    }

    @Override
    public boolean onKeyDown( int keyCode, KeyEvent event ) {
        if( ( keyCode == KeyEvent.KEYCODE_BACK ) && wv.canGoBack() ) {
            wv.goBack();
            return true;
        }
        return super.onKeyDown( keyCode, event );
    }

    @Override
    public boolean onCreateOptionsMenu( Menu menu ) {
        super.onCreateOptionsMenu( menu );

        this.myMenu = menu;
        MenuItem item = menu.add( 0, 1, 0, "MAIN PAGE" );
        item.setIcon( R.drawable.home );
        MenuItem item2 = menu.add( 0, 2, 0, "BACK" );
        item2.setIcon( R.drawable.arrowleft );
        MenuItem item3 = menu.add( 0, 3, 0, "Reload" );
        item3.setIcon( R.drawable.s );
        MenuItem item4 = menu.add( 0, 4, 0, "CLEAR CACHE" );
        item4.setIcon( R.drawable.trash );
        MenuItem item5 = menu.add( 0, 5, 0, "Rate" );
        item5.setIcon( R.drawable.vote );
        MenuItem item6 = menu.add( 0, 6, 0, "Exit" );
        item6.setIcon( R.drawable.close );
        return true;
    }

    @Override
    public boolean onOptionsItemSelected( MenuItem item ) {
        switch( item.getItemId() ) {
            case 1:
                wv.loadUrl( "http://mysite.com" );
                break;
            case 2:
                if( wv.canGoBack() ) {
                    wv.goBack();
                }
                break;
            case 3:
                wv.loadUrl( LASTURL );
                break;
            case 4:
                wv.clearCache( true );
                break;
            case 5:
                Intent marketIntent2 = new Intent(Intent.ACTION_VIEW, Uri.parse(
                      "https://play.google.com/store/apps/details?id=" + getPackageName()));
                    startActivity(marketIntent2);
                break;
            case 6:
                finish();
                break;

        }

        return true;
    }

    private void saveSettings( Boolean val ) {
        SharedPreferences settings = getSharedPreferences( PREFS_NAME, 0 );
        SharedPreferences.Editor editor = settings.edit();
        editor.putBoolean( "IMGMODE", val );
        editor.commit();
    }
}
4

3 回答 3

1 
private boolean checkNetwork() {
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = cm.getActiveNetworkInfo();
    if (networkInfo != null && networkInfo.isConnected()) {
        return true;
    } else {
        Toast.makeText(getApplicationContext(),
                "Sorry, Network Unavailable! :(", Toast.LENGTH_LONG).show();
    }
    return false;
}

这个片段帮助了我，希望它也能帮助你。您的用法可能如下所示。

if (!checkNetwork()) {
    //TODO Network Not Available
} else {
    //TODO Network Available    
}

您可能希望将Toast notification NOT放在function().

于 2013-07-26T12:55:01.517 回答
0

检查此链接 如何检查 android 中的互联网连接？

在加载 url 之前使用相同的解决方案。如果互联网不可用，则显示错误对话框，否则加载 url

于 2012-04-22T19:22:18.583 回答
0

这是我用于网络连接的辅助类：

public class NetworkUtils
{

    public static boolean isOnline( Service service )
    {
        ConnectivityManager cm = (ConnectivityManager) service.getSystemService( Context.CONNECTIVITY_SERVICE );

        NetworkInfo netInfo = cm.getActiveNetworkInfo();

        if ( netInfo != null && netInfo.isConnected() )
        {
            return true;
        }

        return false;
    }

}

并且不要忘记将权限添加到 AndroidManifest.xml：

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>
于 2012-04-22T19:22:44.543 回答