如何获取根据 JAVA 中的用户选择而变化的 JsonObjects?
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【中文标题】如何获取根据 JAVA 中的用户选择而变化的 JsonObjects?【英文标题】:How can I fetch JsonObjects that change according to user selection in JAVA? 【发布时间】:2021-07-13 06:11:12 【问题描述】:我正在使用免费货币转换器 API 开发货币转换器应用程序,我设法将 JSON 提取到 Logcat 中,但我需要从中获取 JSON 对象的值 这是 JSON:
"USD_INR": 74.61395
印度卢比和美元会根据用户的选择而变化,所以我怎样才能将数据输入我的应用程序,如下所示: 示例:
weatherData.mCity = jsonObject.getString("name");
这是我的代码:
package com.example.currencyconverter;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.JsonHttpResponseHandler;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import cz.msebera.android.httpclient.Header;
import static com.loopj.android.http.AsyncHttpClient.log;
public class MainActivity extends AppCompatActivity
// https://free.currconv.com/api/v7/convert?q=USD_INR&compact=ultra&apiKey=38b9f7e70c1b1eb6089e
private String URL = "https://free.currconv.com/api/v7/convert?q=";
private final String URL_BALANCE = "&compact=ultra&apiKey=38b9f7e70c1b1eb6089e";
private final String API_KEY = "38b9f7e70c1b1eb6089e";
String result;
String[] currency1;
String[] currency2;
String name;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Spinner spinner1 = findViewById(R.id.spinner1);
Spinner spinner2 = findViewById(R.id.spinner2);
Button myButton = findViewById(R.id.button);
currency1 = new String[1];
currency2 = new String[1];
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.currency_array, R.layout.custom_spinner);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner1.setAdapter(adapter);
spinner1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id)
currency1[0] = parent.getItemAtPosition(position).toString();
Log.d("myApp", "currency:" + currency1[0]);
name = '\u0022' + currency1[0] + "_" + currency2[0] + '\u0022';
@Override
public void onNothingSelected(AdapterView<?> parent)
);
spinner2.setAdapter(adapter);
spinner2.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id)
currency2[0] = parent.getItemAtPosition(position).toString();
Log.d("myApp", "currency:" + currency2[0]);
name = '\u0022' + currency1[0] + "_" + currency2[0] + '\u0022';
@Override
public void onNothingSelected(AdapterView<?> parent)
);
myButton.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
String finalURL = URL + currency1[0] + "_" + currency2[0] + URL_BALANCE;
log.d("myApp", "url:" + finalURL);
Log.d("myApp", "json:" + name);
networking(finalURL);
);
private void networking(String url)
AsyncHttpClient client = new AsyncHttpClient();
client.get(url, new JsonHttpResponseHandler()
@Override
public void onSuccess(int statusCode, Header[] headers, JSONObject response)
Log.d("myApp", "JSON" + response.toString());
try
result = response.getString(name);
Log.d("myApp", "result" + result);
catch (JSONException e)
e.printStackTrace();
@Override
public void onFailure(int statusCode, Header[] headers, Throwable throwable, JSONObject errorResponse)
Log.d("myApp", "Request Failed:" + statusCode);
Log.d("myApp", "Response Fail:" + errorResponse);
Log.d("myApp", "Error:" + throwable.toString());
);
这是我得到的输出:
2021-04-19 08:17:00.803 16457-16457/com.example.currencyconverter D/myApp: currency:USD
2021-04-19 08:17:03.877 16457-16457/com.example.currencyconverter D/myApp: currency:INR
2021-04-19 08:17:04.962 16457-16457/com.example.currencyconverter V/myApp: url:https://free.currconv.com/api/v7/convert?q=USD_INR&compact=ultra&apiKey=38b9f7e70c1b1eb6089e
2021-04-19 08:17:04.962 16457-16457/com.example.currencyconverter D/myApp: json:"USD_INR"
2021-04-19 08:17:06.287 16457-16457/com.example.currencyconverter D/myApp: JSON"USD_INR":74.61395
【问题讨论】:
【参考方案1】:使用 jsonObject.keys() 获取 JSON 对象的所有键。然后您可以循环返回值并请求与该键关联的值。
【讨论】:
【参考方案2】:我找到了解决办法:
Iterator<String> keys = response.keys();
while (keys.hasNext())
String keyValue = keys.next();
String valueString = response.getString(keyValue);
【讨论】:
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