你好编码员在那里!
我是Android编程的初学者,我的应用程序不会显示没有可用的连接:
显示:404 HTML-screen | 应该显示:消息“没有网络连接”
感谢您的帮助!
package net.schwarzis.htl_cloud;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
@SuppressLint("JavascriptInterface") public class MainActivity extends Activity {
/** Called when the activity is first created. */
private WebView browser = null;
public boolean isOnline() {
ConnectivityManager cm =
(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting()) {
// 1. Instantiate an AlertDialog.Builder with its constructor
AlertDialog.Builder builder = new AlertDialog.Builder(this);
// 2. Chain together various setter methods to set the dialog characteristics
builder.setMessage("Please connect to the internet...")
.setTitle("No network connection!");
// 3. Get the AlertDialog from create()
AlertDialog dialog = builder.create();
builder.show();
return true;
}
return false;
}
public boolean shouldOverrideUrlLoading(WebView view, String url) {
browser.loadUrl(url);
return true;
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// connect to our browser so we can manipulate it
browser = (WebView) findViewById(R.id.mybrowser);
// get settings so we can config our WebView instance
WebSettings settings = browser.getSettings();
// JavaScript? Of course!
settings.setJavaScriptEnabled(true);
// clear cache
browser.clearCache(true);
final ProgressDialog pd=new ProgressDialog(this);
pd.setMessage("Lade...");
browser.setWebViewClient(new WebViewClient() {
public void onPageFinished(WebView view, String url) {
pd.dismiss();
}
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
pd.show();
browser.loadUrl(url);
return true;
}
});
// this is necessary for "alert()" to work
browser.setWebChromeClient(new WebChromeClient());
// add our custom functionality to the javascript environment
browser.addJavascriptInterface(new MyCoolJSHandler(), "Cloud");
// load a page to get things started
pd.show();
browser.loadUrl("http://cloud.schwarzis.net");
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
final ProgressDialog pd=new ProgressDialog(this);
pd.setMessage("Lade...");
if(event.getAction() == KeyEvent.ACTION_DOWN){
switch(keyCode)
{
case KeyEvent.KEYCODE_BACK:
if(browser.canGoBack() == true){
pd.show();
browser.goBack();
}else{
pd.show();
finish();
}
pd.dismiss();
return true;
}
}
return super.onKeyDown(keyCode, event);
}
final class MyCoolJSHandler
{
// write to LogCat (Info)
public void Info(String str) {
Log.i("GoingNative",str);
}
// write to LogCat (Error)
public void Error(String str) {
Log.e("GoingNative",str);
}
// Kill the app
public void EndApp() {
finish();
}
}
}
答案 0 :(得分:0)
确保您在清单文件中添加了“Internet”权限。
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
除此之外,你的代码对我来说很好。
希望它有所帮助。