Question

我正在尝试在用户登录时显示进度对话框。（应用程序连接到在线mysqldatabase）。我关闭了网络连接，但进度对话框没有被解除。

如果没有互联网连接，如何关闭进度对话框？

public class BackgroundLogin extends AsyncTask<String,Void,String> {
Context ctx;
ProgressDialog progressDialog;
BackgroundLogin(Context ctx)
{
    this.ctx=ctx;
}


@Override
protected void onPreExecute() {
    progressDialog = new ProgressDialog(ctx);
    progressDialog.setTitle("Please Wait..");
    progressDialog.setMessage("Signing in..");
    progressDialog.setMax(5);
    progressDialog.setCancelable(true);
    progressDialog.show();

}


@Override
protected void onPostExecute(String result) {
    try {

        if (result.equals("interdit")) {
            progressDialog.dismiss();
            Toast.makeText(ctx, "Access forbidden", Toast.LENGTH_SHORT).show();
        }
        else

        if (result.equals("invalid")) {
            progressDialog.dismiss();
            Toast.makeText(ctx, "Invalid username or password", Toast.LENGTH_SHORT).show();
        }
        else

        {
           progressDialog.dismiss();
            Intent i = new Intent(ctx, HomeScreen.class);
            i.putExtra("username", result);


            ctx.startActivity(i);

        }


    } catch (NullPointerException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    }
}


@Override
protected String doInBackground(String... params) {


    String reg_url="http://www.androidiut20.netai.net/verification.php";
    String username=params[0];
    String password=params[1];
    String langue=params[2];
    String connection=params[3];


        try {
            URL url = new URL(reg_url);


            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String data = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8") + "&" +
                    URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8") + "&" +
                    URLEncoder.encode("langue", "UTF-8") + "=" + URLEncoder.encode(langue, "UTF-8");
            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
            String response = "";
            String line = "";
            while ((line = bufferedReader.readLine()) != null) {
                response += line;


            }
            Thread.sleep(1000);
            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return response;

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }


    return null;


}


}

Answer 1

在doInBackground中检查互联网连接的可用性，如下所示

     if(!isNetworkAvailable()){
       progressDialog.dismiss();
       }

以下是方法

  public static boolean isNetworkAvailable(final Context context) {
    boolean isNetAvailable = false;
    if (context != null) {
        final ConnectivityManager mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (mConnectivityManager != null) {
            final NetworkInfo activeNetwork = mConnectivityManager.getActiveNetworkInfo();
            if(activeNetwork != null) isNetAvailable = true;
        }
    }
    return isNetAvailable;
}

Answer 2

在doInBackground中

catch (Exception e) {
    e.printStackTrace();
    progressDialog.dismiss();
}

Answer 3

在启动AsyncTask之前检查互联网

接受类isInternetConnection boolean

picture

检查互联网

    NSString *url = @"http://somesite.com/";
    NSURL *stringURL = [NSURL URLWithString:url];
    NSLog(@"url-------- %@",stringURL);
    NSData *urlData = [NSData dataWithContentsOfURL:stringURL];
    NSLog(@"data---------%@",urlData);

    if (urlData)
    {
        // JSON successfully downloaded
        NSLog(@"yes ");
    }
    else
    {
        NSLog(@"not exist");
    }

Answer 4

在doInBackground（）里面捕获UnknownHostException ...它是IOException的子类型

@Override
protected String doInBackground(String... params) {
   try{
      //whatever code
   } catch(UnknownHostException e) {
       if (progressDialog.isShowing()) progressDialog.dismiss();
   }

}

Answer 5

在doInBackground（）方法中，只需添加以下逻辑。

＆＃13;

    if(network is not available){
runOnUiThread(new Runnable() {
        @Override
        public void run() {
           if(dialog != null){
           dialog.dismiss();   
          }
     }
});

}

＆＃13;

没有网络连接时关闭进度对话框

5 个答案: