在Android应用程序中无法使用Internet连接时显示警报

Question

在我的应用程序中,数据来自互联网,我正在尝试创建一个功能,检查互联网连接是否可用,如果不是,它会提供一个警报信息,没有互联网连接可用.我正在使用以下代码.但它不起作用.

public void onCreate(Bundle savedInstanceState){
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main1);
  if (isOnline())
  {
   // my code
  }
  else
  {
   Hotgames4meActivity1.this.startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS)); 
    try {
       AlertDialog alertDialog = new AlertDialog.Builder(Hotgames4meActivity1.this).create();

       alertDialog.setTitle("Info");
       alertDialog.setMessage("Internet not available, Cross check your internet connectivity and try again");
       //alertDialog.setIcon(R.drawable.alerticon);
       alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
         public void onClick(DialogInterface dialog, int which) {
          finish();

         }
       });

       alertDialog.show();
    }
    catch(Exception e)
    {
       //Log.d(Constants.TAG, "Show Dialog: "+e.getMessage());
    }
  }
}

Answer 1

public boolean isOnline() {
    ConnectivityManager conMgr = (ConnectivityManager) getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo netInfo = conMgr.getActiveNetworkInfo();

    if(netInfo == null || !netInfo.isConnected() || !netInfo.isAvailable()){
        Toast.makeText(context, "No Internet connection!", Toast.LENGTH_LONG).show();
        return false;
    }
return true; 
}

并且您必须添加用于访问网络状态和Internet的预留:

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

Answer 2

public void onCreate(Bundle obj) {
    super.onCreate(obj)
    setContextView(layout);

    if (isOnline()) {
        //do whatever you want to do 
    } else {
        try {
            AlertDialog alertDialog = new AlertDialog.Builder(con).create();

            alertDialog.setTitle("Info");
            alertDialog.setMessage("Internet not available, Cross check your internet connectivity and try again");
            alertDialog.setIcon(android.R.drawable.ic_dialog_alert);
            alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    finish();

                }
            });

            alertDialog.show();
        } catch (Exception e) {
            Log.d(Constants.TAG, "Show Dialog: " + e.getMessage());
        }
    }
}

Answer 3

您可以在任何地方使用这些方法

public void checkNetworkConnection(){
    AlertDialog.Builder builder =new AlertDialog.Builder(this);
    builder.setTitle("No internet Connection");
    builder.setMessage("Please turn on internet connection to continue");
    builder.setNegativeButton("close", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();
        }
    });
    AlertDialog alertDialog = builder.create();
    alertDialog.show();
}

public boolean isNetworkConnectionAvailable(){
    ConnectivityManager cm =
            (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);

    NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
    boolean isConnected = activeNetwork != null &&
            activeNetwork.isConnected();
    if(isConnected) {
        Log.d("Network", "Connected");
        return true;
        }
    else{
        checkNetworkConnection();
        Log.d("Network","Not Connected");
        return false;
    }
}

需要检查连接是否可用时，请调用isNetworkConnectionAvailable（）方法。如果网络不可用，则会弹出对话框。如果需要在多个屏幕中检查网络，请将这些方法添加到超类，并将该类继承到其他类，并在需要时调用此方法