好的，所以我是android studio的新手，并尝试制作货币转换器。我应该使用API，然后对其进行编码以进行转换并从API中获取费率。但是当我运行它时，一切正常，除了它将所有内容都转换为0，忽略用户输入。
由于API，我不得不以这种方式对其进行硬编码，我不知道如何以更简单的方式进行操作。抱歉，添麻烦了。如果需要更多信息，请告知我。
以下是我的转换器所在的MainActivity2的代码：
package com.example.justin.currencyconverter20;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.w3c.dom.Text;
import java.util.List;
public class MainActivity2 extends AppCompatActivity {
private String[] arraySpinner;
private static final String LOGIN_URL = "https://api.fixer.io/latest?base=SGD";
List<Singapore> myCountries;
Singapore tempSingapore;
String operation;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
this.arraySpinner = new String[] {
"AUD",
"BGN",
"BRL",
"CAD",
"CHF",
"CNY",
"CZK",
"DKK",
"GBP",
"HKD",
"HRK",
"HUF",
"IDR",
"ILS",
"INR",
"JPY",
"KRW",
"MXN",
"MYR",
"NOK",
"NZD",
"PHP",
"PLN",
"RON",
"RUB",
"SEK",
"THB",
"TRY",
"USD",
"ZAR",
"EUR"
};
Spinner s = (Spinner) findViewById(R.id.countryspinner1);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, arraySpinner);
s.setAdapter(adapter);
new getRates().execute();
}
JSONParser jsonParser = new JSONParser();
class getRates extends AsyncTask<String, String, JSONArray> {
private ProgressDialog progressDialog;
@Override
protected JSONArray doInBackground(String... args) {
try {
JSONArray json = jsonParser.makeHttpRequest(
LOGIN_URL, "GET");
if (json != null) {
Log.d("JSON result", json.toString());
return json;
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(JSONArray json) {
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
if (json != null) {
// looping through All records
for (int i = 0; i < json.length(); i++) {
try {
JSONObject c = json.getJSONObject(i);
tempSingapore.setName("Singapore");
tempSingapore.setCurrencycode("SGD");
tempSingapore.setAUD(c.getDouble("AUD"));
tempSingapore.setBRL(c.getDouble("BRL"));
tempSingapore.setBGN(c.getDouble("BGN"));
tempSingapore.setCAD(c.getDouble("CAD"));
tempSingapore.setCNY(c.getDouble("CNY"));
tempSingapore.setCHF(c.getDouble("CHF"));
tempSingapore.setCZK(c.getDouble("CZK"));
tempSingapore.setDKK(c.getDouble("DKK"));
tempSingapore.setEUR(c.getDouble("EUR"));
tempSingapore.setGBP(c.getDouble("GBP"));
tempSingapore.setHKD(c.getDouble("HKD"));
tempSingapore.setHRK(c.getDouble("HRK"));
tempSingapore.setHUF(c.getDouble("HUF"));
tempSingapore.setIDR(c.getDouble("IDR"));
tempSingapore.setILS(c.getDouble("ILS"));
tempSingapore.setINR(c.getDouble("INR"));
tempSingapore.setJPY(c.getDouble("JPY"));
tempSingapore.setKRW(c.getDouble("KRW"));
tempSingapore.setMXN(c.getDouble("MXN"));
tempSingapore.setMYR(c.getDouble("MYR"));
tempSingapore.setNOK(c.getDouble("NOK"));
tempSingapore.setNZD(c.getDouble("NZD"));
tempSingapore.setPHP(c.getDouble("PHP"));
tempSingapore.setPLN(c.getDouble("PLN"));
tempSingapore.setRON(c.getDouble("RON"));
tempSingapore.setRUB(c.getDouble("RUB"));
tempSingapore.setSEK(c.getDouble("SEK"));
tempSingapore.setTRY(c.getDouble("TRY"));
tempSingapore.setTHB(c.getDouble("THB"));
tempSingapore.setUSD(c.getDouble("USD"));
tempSingapore.setZAR(c.getDouble("ZAR"));
String AUD = String.valueOf(c.getDouble("AUD"));
Toast myToast = Toast.makeText(getApplicationContext(), AUD, Toast.LENGTH_SHORT);
myToast.show();
} catch (JSONException e) {
e.printStackTrace();
}
}
populate();
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void populate() {
}
public void btnGetRates (View v){
new getRates().execute();
TextView textView = (TextView) findViewById(R.id.textView3);
Spinner tempSpinner = (Spinner) findViewById(R.id.countryspinner1);
EditText editText = (EditText) findViewById(R.id.editText);
double userText = Double.parseDouble(editText.getText().toString());
String valOfSpinner = tempSpinner.getSelectedItem().toString();
Singapore mySingapore = new Singapore();
double rates = 0;
if (valOfSpinner.equals("AUD") )
{
mySingapore.getAUD();
rates = mySingapore.getAUD();
}
else if (valOfSpinner.equals("BGN"))
{
mySingapore.getBGN();
rates = mySingapore.getBGN();
}
else if (valOfSpinner.equals("BRL"))
{
mySingapore.getBRL();
rates = mySingapore.getBRL();
}
else if (valOfSpinner.equals("CAD"))
{
mySingapore.getCAD();
rates = mySingapore.getCAD();
}
else if (valOfSpinner.equals("CHF"))
{
mySingapore.getCHF();
rates = mySingapore.getCHF();
}
else if (valOfSpinner.equals("CNY"))
{
mySingapore.getCNY();
rates = mySingapore.getCNY();
}
else if (valOfSpinner.equals("CZK"))
{
mySingapore.getCZK();
rates = mySingapore.getCZK();
}
else if (valOfSpinner.equals("DKK"))
{
mySingapore.getDKK();
rates = mySingapore.getDKK();
}
else if (valOfSpinner.equals("GBP"))
{
mySingapore.getGBP();
rates = mySingapore.getGBP();
}
else if (valOfSpinner.equals("HKD"))
{
mySingapore.getHKD();
rates = mySingapore.getHKD();
}
else if (valOfSpinner.equals("HRK"))
{
mySingapore.getHRK();
rates = mySingapore.getHRK();
}
else if (valOfSpinner.equals("HUF"))
{
mySingapore.getHUF();
rates = mySingapore.getHUF();
}
else if (valOfSpinner.equals("IDR"))
{
mySingapore.getIDR();
rates = mySingapore.getIDR();
}
else if (valOfSpinner.equals("ILS"))
{
mySingapore.getILS();
rates = mySingapore.getILS();
}
else if (valOfSpinner.equals("INR"))
{
mySingapore.getINR();
rates = mySingapore.getINR();
}
else if (valOfSpinner.equals("JPY"))
{
mySingapore.getJPY();
rates = mySingapore.getJPY();
}
else if (valOfSpinner.equals("KRW"))
{
mySingapore.getKRW();
rates = mySingapore.getKRW();
}
else if (valOfSpinner.equals("MYR"))
{
mySingapore.getMYR();
rates = mySingapore.getMYR();
}
else if (valOfSpinner.equals("MXN"))
{
mySingapore.getMXN();
rates = mySingapore.getMXN();
}
else if (valOfSpinner.equals("NOK"))
{
mySingapore.getNOK();
rates = mySingapore.getNOK();
}
else if (valOfSpinner.equals("NZD"))
{
mySingapore.getNZD();
rates = mySingapore.getNZD();
}
else if (valOfSpinner.equals("PHP"))
{
mySingapore.getPHP();
rates = mySingapore.getPHP();
}
else if (valOfSpinner.equals("PLN"))
{
mySingapore.getPLN();
rates = mySingapore.getPLN();
}
else if (valOfSpinner.equals("RON"))
{
mySingapore.getRON();
rates = mySingapore.getRON();
}
else if (valOfSpinner.equals("RUB"))
{
mySingapore.getRUB();
rates = mySingapore.getRUB();
}
else if (valOfSpinner.equals("SEK"))
{
mySingapore.getSEK();
rates = mySingapore.getSEK();
}
else if (valOfSpinner.equals("THB"))
{
mySingapore.getTHB();
rates = mySingapore.getTHB();
}
else if (valOfSpinner.equals("TRY"))
{
mySingapore.getTRY();
rates = mySingapore.getTRY();
}
else if (valOfSpinner.equals("USD"))
{
mySingapore.getUSD();
rates = mySingapore.getUSD();
}
else if (valOfSpinner.equals("ZAR"))
{
mySingapore.getZAR();
rates = mySingapore.getZAR();
}
else if (valOfSpinner.equals("EUR"))
{
mySingapore.getEUR();
rates = mySingapore.getEUR();
}
double rateResult = userText * rates;
String result = String.valueOf(rateResult);
textView.setText(result);
}
}
Edit2我的jsonparser类：
package com.example.justin.currencyconverter20;
import android.util.Log;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;
public class JSONParser {
String charset = "UTF-8";
HttpURLConnection conn;
DataOutputStream wr;
StringBuilder result;
URL urlObj;
JSONArray Obj = null;
StringBuilder sbParams;
String paramsString;
public JSONArray makeHttpRequest(String url, String method) {
int i = 0;
if(method.equals("GET")){
try {
urlObj = new URL(url);
conn = (HttpURLConnection) urlObj.openConnection();
conn.setDoOutput(false);
conn.setRequestMethod("GET");
conn.setConnectTimeout(15000);
conn.connect();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
//Receive the response from the server
InputStream in = new BufferedInputStream(conn.getInputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
result = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
result.append(line);
}
Log.d("JSON Parser", "result: " + result.toString());
} catch (IOException e) {
// e.printStackTrace();
}
conn.disconnect();
// try parse the string to a JSON object
try {
JSONObject jObj = new JSONObject(result.toString());
JSONObject ratesObject = jObj.getJSONObject("rates");
double AUD = ratesObject.getDouble("AUD");
double BGN = ratesObject.getDouble("BGN");
double BRL = ratesObject.getDouble("BRL");
double CAD = ratesObject.getDouble("CAD");
double CHF = ratesObject.getDouble("CHF");
double CNY = ratesObject.getDouble("CNY");
double CZK = ratesObject.getDouble("CZK");
double DKK = ratesObject.getDouble("DKK");
double GBP = ratesObject.getDouble("GBP");
double HKD = ratesObject.getDouble("HKD");
double HRK = ratesObject.getDouble("HRK");
double HUF = ratesObject.getDouble("HUF");
double IDR = ratesObject.getDouble("IDR");
double ILS = ratesObject.getDouble("ILS");
double INR = ratesObject.getDouble("INR");
double JPY = ratesObject.getDouble("JPY");
double KRW = ratesObject.getDouble("KRW");
double MXN = ratesObject.getDouble("MXN");
double MYR = ratesObject.getDouble("MYR");
double NOK = ratesObject.getDouble("NOK");
double NZD = ratesObject.getDouble("NZD");
double PHP = ratesObject.getDouble("PHP");
double PLN = ratesObject.getDouble("PLN");
double RON = ratesObject.getDouble("RON");
double RUB = ratesObject.getDouble("RUB");
double SEK = ratesObject.getDouble("SEK");
double THB = ratesObject.getDouble("THB");
double TRY = ratesObject.getDouble("TRY");
double USD = ratesObject.getDouble("USD");
double ZAR = ratesObject.getDouble("ZAR");
double EUR = ratesObject.getDouble("EUR");
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON Object
return Obj;
}
}
使用JSONlint编辑我的JSON：
{
"base": "SGD",
"date": "2016-02-26",
"rates": {
"AUD": 0.99008,
"BGN": 1.2677,
"BRL": 2.8102,
"CAD": 0.96636,
"CHF": 0.70839,
"CNY": 4.6639,
"CZK": 17.542,
"DKK": 4.8354,
"GBP": 0.5104,
"HKD": 5.5426,
"HRK": 4.941,
"HUF": 201.27,
"IDR": 9537.9,
"ILS": 2.7826,
"INR": 49.002,
"JPY": 80.646,
"KRW": 881.73,
"MXN": 12.914,
"MYR": 3.0044,
"NOK": 6.1735,
"NZD": 1.0596,
"PHP": 33.884,
"PLN": 2.828,
"RON": 2.8934,
"RUB": 53.827,
"SEK": 6.074,
"THB": 25.432,
"TRY": 2.0966,
"USD": 0.71338,
"ZAR": 11.183,
"EUR": 0.64817
}
}
Edit4：
解析是可以的，但在调用方法btnGetRates之后似乎无法在我的转换器中获取它。以下是我的新加坡。设置并获得费率：
public class Singapore {
private String name;
private double AUD;
private double BGN;
private double BRL;
private double CAD;
private double CHF;
private double CNY;
private double CZK;
private double DKK;
private double GBP;
private double HKD;
private double HRK;
private double HUF;
private double IDR;
private double ILS;
private double INR;
private double JPY;
private double KRW;
private double MXN;
private double MYR;
private double NOK;
private double NZD;
private double PHP;
private double PLN;
private double RON;
private double RUB;
private double SEK;
private double THB;
private double TRY;
private double USD;
private double ZAR;
private double EUR;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getAUD() {
return AUD;
}
public void setAUD(double AUD) {
this.AUD = AUD;
}
public double getBGN() {
return BGN;
}
public void setBGN(double BGN) {
this.BGN = BGN;
}
public double getBRL() {
return BRL;
}
public void setBRL(double BRL) {
this.BRL = BRL;
}
public double getCAD() {
return CAD;
}
public void setCAD(double CAD) {
this.CAD = CAD;
}
public double getCHF() {
return CHF;
}
public void setCHF(double CHF) {
this.CHF = CHF;
}
public double getCNY() {
return CNY;
}
public void setCNY(double CNY) {
this.CNY = CNY;
}
public double getCZK() {
return CZK;
}
public void setCZK(double CZK) {
this.CZK = CZK;
}
public double getDKK() {
return DKK;
}
public void setDKK(double DKK) {
this.DKK = DKK;
}
public double getGBP() {
return GBP;
}
public void setGBP(double GBP) {
this.GBP = GBP;
}
public double getHKD() {
return HKD;
}
public void setHKD(double HKD) {
this.HKD = HKD;
}
public double getHRK() {
return HRK;
}
public void setHRK(double HRK) {
this.HRK = HRK;
}
public double getHUF() {
return HUF;
}
public void setHUF(double HUF) {
this.HUF = HUF;
}
public double getIDR() {
return IDR;
}
public void setIDR(double IDR) {
this.IDR = IDR;
}
public double getILS() {
return ILS;
}
public void setILS(double ILS) {
this.ILS = ILS;
}
public double getINR() {
return INR;
}
public void setINR(double INR) {
this.INR = INR;
}
public double getJPY() {
return JPY;
}
public void setJPY(double JPY) {
this.JPY = JPY;
}
public double getKRW() {
return KRW;
}
public void setKRW(double KRW) {
this.KRW = KRW;
}
public double getMXN() {
return MXN;
}
public void setMXN(double MXN) {
this.MXN = MXN;
}
public double getMYR() {
return MYR;
}
public void setMYR(double MYR) {
this.MYR = MYR;
}
public double getNOK() {
return NOK;
}
public void setNOK(double NOK) {
this.NOK = NOK;
}
public double getNZD() {
return NZD;
}
public void setNZD(double NZD) {
this.NZD = NZD;
}
public double getPHP() {
return PHP;
}
public void setPHP(double PHP) {
this.PHP = PHP;
}
public double getPLN() {
return PLN;
}
public void setPLN(double PLN) {
this.PLN = PLN;
}
public double getRON() {
return RON;
}
public void setRON(double RON) {
this.RON = RON;
}
public double getRUB() {
return RUB;
}
public void setRUB(double RUB) {
this.RUB = RUB;
}
public double getSEK() {
return SEK;
}
public void setSEK(double SEK) {
this.SEK = SEK;
}
public double getTHB() {
return THB;
}
public void setTHB(double THB) {
this.THB = THB;
}
public double getTRY() {
return TRY;
}
public void setTRY(double TRY) {
this.TRY = TRY;
}
public double getUSD() {
return USD;
}
public void setUSD(double USD) {
this.USD = USD;
}
public double getZAR() {
return ZAR;
}
public void setZAR(double ZAR) {
this.ZAR = ZAR;
}
public double getEUR() {
return EUR;
}
public void setEUR(double EUR) {
this.EUR = EUR;
}
}
解析的结果：
03-01 05:23:36.050 13219-13400/com.example.justin.currencyconverter20 D/JSON Parser: result: {"base":"SGD","date":"2016-02-29","rates":{"AUD":0.99576,"BGN":1.2762,"BRL":2.8316,"CAD":0.96359,"CHF":0.71217,"CNY":4.6559,"CZK":17.655,"DKK":4.868,"GBP":0.51276,"HKD":5.5237,"HRK":4.9764,"HUF":203.11,"IDR":9500.4,"ILS":2.7769,"INR":48.537,"JPY":80.352,"KRW":879.31,"MXN":12.92,"MYR":2.9931,"NOK":6.2018,"NZD":1.0804,"PHP":33.68,"PLN":2.8413,"RON":2.9205,"RUB":53.927,"SEK":6.0828,"THB":25.336,"TRY":2.1059,"USD":0.71047,"ZAR":11.391,"EUR":0.65253}}
在更改解析器后仍将任何值转换为0。
答案 0 :(得分：2)
您需要使用已保存费率的对象（即tempSingapore）。你没有这样做，而是使用一个没有数据集的新对象，导致转换为0。
初始化您的变量，如Singapore tempSingapore = new Singapore ();然后
更改
Singapore mySingapore = new Singapore();
到
Singapore mySingapore = tempSingapore;
btnGetRates 中的
更新：刚看到您的JSON也无效。在http://jsonlint.com/
检查您的JSON