Question

我想在登录成功后开始一项新活动。这是当登录正确时，一个新的活动应该自动启动...我不知道在哪里提到startactivity。请帮我这个，我是android的新手。这是我的代码......

    public class BackgroundTask extends AsyncTask<String,Void,String> {
    AlertDialog alertDialog;
    Context ctx;
    BackgroundTask(Context ctx)
    {
        this.ctx =ctx;
    }
    @Override
    protected void onPreExecute() {
        alertDialog = new AlertDialog.Builder(ctx).create();
        alertDialog.setTitle("Login Information....");
    }

    @Override
    protected String doInBackground(String... params) {
        String reg_url = "";
        String login_url = "";
        String method = params[0];
        if (method.equals("register")) {
            String name = params[1];
            String user_name = params[2];
            String user_pass = params[3];
            try {
                URL url = new URL(reg_url);
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.setRequestMethod("POST");
                httpURLConnection.setDoOutput(true);

                //httpURLConnection.setDoInput(true);
                OutputStream OS = httpURLConnection.getOutputStream();
                BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
                String data = URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8") + "&" +
                        URLEncoder.encode("user_name", "UTF-8") + "=" + URLEncoder.encode(user_name, "UTF-8") + "&" +
                        URLEncoder.encode("user_pass", "UTF-8") + "=" + URLEncoder.encode(user_pass, "UTF-8");
                bufferedWriter.write(data);
                bufferedWriter.flush();
                bufferedWriter.close();
                OS.close();
                InputStream IS = httpURLConnection.getInputStream();
                IS.close();
                //httpURLConnection.connect();
                httpURLConnection.disconnect();
                return "Registration Success...";
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        else if(method.equals("login"))
        {
            String login_name = params[1];
            String login_pass = params[2];
            try {
                URL url = new URL(login_url);
                HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
                httpURLConnection.setRequestMethod("POST");
                httpURLConnection.setDoOutput(true);
                httpURLConnection.setDoInput(true);
                OutputStream outputStream = httpURLConnection.getOutputStream();
                BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));
                String data = URLEncoder.encode("login_name","UTF-8")+"="+URLEncoder.encode(login_name,"UTF-8")+"&"+
                        URLEncoder.encode("login_pass","UTF-8")+"="+URLEncoder.encode(login_pass,"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;
                }
                bufferedReader.close();
                inputStream.close();
                httpURLConnection.disconnect();
                return response;


            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }


        }
        return null;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
    }

    @Override
    protected void onPostExecute(String result) {
        if(result.equals("Registration Success..."))
        {
            Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
        }
        else
        {
            alertDialog.setMessage(result);
            alertDialog.show();
        }

    }
}

Answer 1

您可以将on intent放在onPostExecute方法中，如下所示：

@Override
    protected void onPostExecute(String result) {
        if(result == null)
        {
            // do what you want to do
        }
        else if(result.equals("Registration Success..."))
        {
            Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
        }
        else if(result.contains("Login Success")) // msg you get from success like "Login Success"
        {
            Intent i = new Intent(ctx,NewActivity.class);
            ctx.startActivity(i);
            alertDialog.setMessage(result);
            alertDialog.show();
        }

    }

修改： 如果您想在登录成功后调用新活动，则将意图放入else部分。

Answer 2

试试这个

Intent intent = new Intent(MainActivity.this, Second.class);
startActivity(intent);

Answer 3

在postExecute（）方法中，你必须检查方法变量，请检查下面的代码。

public class BackgroundTask extends AsyncTask<String,Void,String> {
AlertDialog alertDialog;
Context ctx;
String method;
BackgroundTask(Context ctx)
{
    this.ctx =ctx;
}
@Override
protected void onPreExecute() {
    alertDialog = new AlertDialog.Builder(ctx).create();
    alertDialog.setTitle("Login Information....");
}

@Override
protected String doInBackground(String... params) {
    String reg_url = "http://thecapitalcitychurch.16mb.com/new/register.php";
    String login_url = "http://thecapitalcitychurch.16mb.com/new/login.php";
    method = params[0];
    if (method.equals("register")) {
        String name = params[1];
        String user_name = params[2];
        String user_pass = params[3];
        try {
            URL url = new URL(reg_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);

            //httpURLConnection.setDoInput(true);
            OutputStream OS = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
            String data = URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8") + "&" +
                    URLEncoder.encode("user_name", "UTF-8") + "=" + URLEncoder.encode(user_name, "UTF-8") + "&" +
                    URLEncoder.encode("user_pass", "UTF-8") + "=" + URLEncoder.encode(user_pass, "UTF-8");
            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            OS.close();
            InputStream IS = httpURLConnection.getInputStream();
            IS.close();
            //httpURLConnection.connect();
            httpURLConnection.disconnect();
            return "Registration Success...";
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    else if(method.equals("login"))
    {
        String login_name = params[1];
        String login_pass = params[2];
        try {
            URL url = new URL(login_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));
            String data = URLEncoder.encode("login_name","UTF-8")+"="+URLEncoder.encode(login_name,"UTF-8")+"&"+
                    URLEncoder.encode("login_pass","UTF-8")+"="+URLEncoder.encode(login_pass,"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;
            }
            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return response;


        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }


    }
    return null;
}

@Override
protected void onProgressUpdate(Void... values) {
    super.onProgressUpdate(values);
}

@Override
protected void onPostExecute(String result) {
    if(result.equals("Registration Success..."))
    {
        Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
    }
    else
    {
        alertDialog.setMessage(result);
        alertDialog.show();
    }

    if(method.equals("login") && result.equals("Login Success..."))
    {
        Intent intent=new Intent(ctx, Dashboard.class);
        ctx.startActivity(intent);
    }
}
}

Answer 4

调用onPostexecute

    protected void onPostExecute(String response) {
        try {Intent intent = new Intent(context, MainActivity.class);
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(intent);
}catch(Exception e){}}

Answer 5

当您想要在登录调用成功后启动另一个活动时，您可以从登录响应的回调或AsyncTask的onpostExecute方法启动另一个活动。

为了在API流程中实现回调，你只需要创建一个没有body（只有声明）的方法，这些方法必须在实现该接口的类中实现。将此接口对象作为asyncTask的构造函数传递。一旦登录调用成功，您需要调用该接口的方法，并在该方法内部启动另一个活动。

登录成功后如何开始新活动？

5 个答案: