Question

我是异步任务的新手，并尝试创建登录UI。当我使用有效凭据从服务器发出请求时，一切正常。当凭据不正确时，我使用一组“if”语句来检查响应的错误代码是什么并打印相应的消息。对于响应为空的情况，我也有这样的消息。我可以从服务器的部分看到所有响应都包含状态代码，即使凭据无效也是如此。此外，我可以通过在代码中使用检查点来查看状态代码。但是当我尝试从无效凭据获得的响应中提取状态代码时，唯一有效的“if”语句是检查响应是否等于“”的语句。其他“如果”陈述的任何条件都不符合要求。这是我的代码：

public String GET(String u) {
    HttpURLConnection httpURLConnection = null;
    BufferedReader bufferedReader;
    StringBuilder stringBuilder;
    String line;
    String jsonString = "";

    try {
        URL url = new URL(u);
        httpURLConnection = (HttpURLConnection) url.openConnection();
        httpURLConnection.setRequestMethod("GET");
        bufferedReader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
        stringBuilder = new StringBuilder();

        while ((line = bufferedReader.readLine()) != null) {
            stringBuilder.append(line + '\n');
        }
        jsonString = stringBuilder.toString();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        httpURLConnection.disconnect();
    }
    return jsonString;
}

public void ProcessResponse(String response) {
    if(response!="") {
        try {
            json = new JSONObject(response);
        } catch (JSONException e) {
            e.printStackTrace();
        }

        try {
            status = json.getInt("status_code");

            if (status == 500) {
                Toast.makeText(this, "Internal server error! Please repeat action!", Toast.LENGTH_SHORT).show();
            } else if(status == 401) {
                Toast.makeText(this, "Invalid credentials", Toast.LENGTH_SHORT).show();
            } else if(status == 400) {
                Toast.makeText(this, "Bad Request! Please repeat action!", Toast.LENGTH_SHORT).show();
            } else if(status == 200) {
                try {
                    SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
                    editor.putString("base_url", baseURL);
                    editor.putInt("store_id", json.getInt("store_id"));
                    editor.putInt("pin", json.getInt("pin_number"));
                    editor.putInt("delete_table",json.getInt("delele_table_id"));
                    editor.commit();
                } catch (JSONException e) {
                    e.printStackTrace();
                }

                Intent intent = new Intent(getApplicationContext(), APICall.class);
                intent.putExtra("Action","Main Menu");
                startActivity(intent);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    } else {
        Toast.makeText(LoginActivity.this, "Problem encountered!", Toast.LENGTH_SHORT).show();
    }
}

private class ServerCall extends AsyncTask<String, Void, String> {

    @Override
    protected String doInBackground(String... params) {
        String url = params[0];
        return GET(url);
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        ProcessResponse(s);
    }
}

这些函数在代码的另一部分中使用执行函数调用，通常在AsyncTask中完成。

提前感谢您的帮助！

编辑：该函数调用如下：

public class LoginActivity extends AppCompatActivity {

    public static final String MY_PREFS_NAME = "Shared Preferences";
    String url = "";
    String baseURL = "";
    int status = 0;
    JSONObject json = null;

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

        Button login = (Button) findViewById(R.id.login_button);
        CheckBox mode = (CheckBox) findViewById(R.id.login_development_mode);

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText developerURL = (EditText) findViewById(R.id.base_url);
                EditText store = (EditText) findViewById(R.id.store_id_field);
                EditText pin = (EditText) findViewById(R.id.pin_field);

                baseURL = developerURL.getText().toString();

                url = baseURL + "/api/auth/check?store_id="+store.getText().toString()+
                        "&pin_number="+pin.getText().toString();
                ServerCall loginCall = new ServerCall();
                loginCall.execute(url);
            }
        });

       /*more code, including the AsyncTask mentioned above*/
    }

Answer 1

我找到了问题的答案。谢谢大家的回复。我更改了GET和processResponse方法如下：

public String GET(String u) {
    HttpURLConnection httpURLConnection = null;
    BufferedReader bufferedReader;
    StringBuilder stringBuilder;
    String line;
    String jsonString = "";
    int code = -1;

    try {
        URL url = new URL(u);
        httpURLConnection = (HttpURLConnection) url.openConnection();
        httpURLConnection.setRequestMethod("GET");

        code = httpURLConnection.getResponseCode();

        bufferedReader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
        stringBuilder = new StringBuilder();

        while ((line = bufferedReader.readLine()) != null) {
            stringBuilder.append(line + '\n');
        }
        jsonString = stringBuilder.toString();
    } catch (Exception e) {
        e.printStackTrace();
        status = code;
        return "";
    } finally {
        httpURLConnection.disconnect();
    }
    return jsonString;
}

public void ProcessResponse(String response) {

    if (status == 500) {
        Toast.makeText(this, "Internal server error! Please repeat action!", Toast.LENGTH_SHORT).show();
    } else if(status == 401) {
        Toast.makeText(this, "Invalid credentials", Toast.LENGTH_SHORT).show();
    } else if(status == 400) {
        Toast.makeText(this, "Bad Request! Please repeat action!", Toast.LENGTH_SHORT).show();
    } else if(status == 200) {
        if(response!="") {
            try {
                json = new JSONObject(response);

                SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
                editor.putString("base_url", baseURL);
                editor.putInt("store_id", json.getInt("store_id"));
                editor.putInt("cell_phone", json.getInt("cell_phone"));
                editor.putInt("pin", json.getInt("pin_number"));
                editor.putInt("delete_table", json.getInt("delele_table_id"));
                editor.commit();
            } catch (JSONException e) {
                e.printStackTrace();
            }

            Intent intent = new Intent(getApplicationContext(), APICall.class);
            intent.putExtra("Action","Main Menu");
            startActivity(intent);
        } else {
            Toast.makeText(LoginActivity.this, "Problem encountered!", Toast.LENGTH_SHORT).show();
        }
    }
}

我不确定我使用httpURLConnection的方式是否最有效，或者我的代码是愚蠢的，但是它有效，所以如果有人有任何改进建议，请随意！再次感谢大家！

收到服务器响应但无法访问状态代码

1 个答案: