java - 当我的验证条件在另一个类中时，如何重定向到另一个 Activity ？

Question

我有一个登录表单，用于验证用户名或密码是否与我的数据库中的用户名或密码匹配，但我在另一个 java 类中编写了验证代码，如下所示:

AlertDialog dialog;
Context context;
public background (Context context){
    this.context = context;
}

@Override
protected void onPreExecute() {
    dialog = new AlertDialog.Builder(context).create();
    dialog.setTitle("Login Status");
}

@Override
protected void onPostExecute(String s) {
    dialog.setMessage(s);
    dialog.show();

}


@Override
protected String doInBackground(String... voids) {
    String result =  "";
    String user = voids[0];
    String pass = voids[1];

    String connStr = "http://xzylrey1.heliohost.org/loginandroid.php";

    try {
        URL url = new URL(connStr);

        HttpURLConnection http = (HttpURLConnection) url.openConnection();
        http.setRequestMethod("POST");
        http.setDoInput(true);
        http.setDoOutput(true);

        OutputStream ops = http.getOutputStream();
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(ops, "UTF-8"));
        String data = URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode(user, "UTF-8")
                + "&&" + URLEncoder.encode("pass", "UTF-8") + "=" + URLEncoder.encode(pass, "UTF-8");

        writer.write(data);
        writer.flush();
        writer.close();
        ops.close();

        InputStream ips = http .getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(ips, "ISO-8859-1"));
        String line = "";
        while((line = reader.readLine()) != null){
            result += line;
        }
        reader.close();
        ips.close();
        http.disconnect();
        return result;

    } catch (MalformedURLException e) {
        result = e.getMessage();
    } catch (IOException e) {
        result = e.getMessage();
    }


    return result;

这是主类:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    et_username =  findViewById(R.id.et_username);
    etPassword =  findViewById(R.id.et_Password);
    btnLogin = findViewById(R.id.btn_Login);



}

public void moveToActivityTwo(){
    Intent intent = new Intent(MainActivity.this, Main2Activity.class);
    startActivity(intent);

}

public void loginBtn(View view) {

    String user = et_username.getText().toString();
    String pass = etPassword.getText().toString();


    background bg = new background(this);
    bg.execute(user, pass);
    moveToActivityTwo();

我尝试将该方法放在 bg.execute 行下方，但它会自动重定向到其他 Activity ，还有其他方法可以做到这一点吗？

Answer 1

您需要将 moveToActivityTwo() 方法移动到 onPostExecute() 方法的末尾。

它看起来像这样:

protected void onPostExecute(String s) {
    dialog.setMessage(s);
    dialog.show();
    context.moveToActivityTwo();
}

它调用回调模式。