查询以在设备未连接到Internet时向用户显示警报

Question

我想要显示消息＆＃34; No Internet Connection＆＃34;如果我的应用在用户访问时未连接到互联网。默认情况下，它显示＆＃34;页面未找到...（网址）＆＃34; 。但我想向用户显示一条消息＆＃34;要检查互联网连接＆＃34;如果在访问我的应用程序时设备未连接到Internet。谁能建议我怎么做？谢谢......

Answer 1

创建一个名为ConnectionDetector的单独类来检测互联网的可用性

public class ConnectionDetector {

    private Context _context;

    public ConnectionDetector(Activity context) {
        this._context = context;
    }

    public boolean isConnectingToInternet() {
        ConnectivityManager connectivity = (ConnectivityManager) _context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        if (connectivity != null) {
            NetworkInfo[] info = connectivity.getAllNetworkInfo();
            if (info != null)
                for (int i = 0; i < info.length;)
                    if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                        return true;
                    }

                    else {
                        showAlertDialog(_context, "No Internet Connection",
                                "You don't have internet connection.");
                        return false;
                    }

        }

        return false;
    }

    public void showAlertDialog(Context context, String title, String message) {
        AlertDialog alertDialog = new AlertDialog.Builder(context).create();

        // Setting Dialog Title
        alertDialog.setTitle(title);

        // Setting Dialog Message
        alertDialog.setMessage(message);

        alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });

        // Showing Alert Message
        alertDialog.show();
    }
}

像这样称呼这个：

   ConnectionDetector connectionDetector = new ConnectionDetector(this);
    if (connectionDetector.isConnectingToInternet()) {
// do your stuff
                }