在我的应用程序中，我需要获取不同货币的当前汇率。正如this建议的那样，this和this question 一个很好的方法是使用 Yahoo Finance 服务。
因此，例如，当我想查找美元和加元之间的汇率时，我只需发送此链接：http://download.finance.yahoo.com/d/quotes.csv?s=USDCAD=X&f=sl1d1t1ba&e=.csv
这适用于我的带有 Android 2.3.4 的 Motorola Atrix 手机和带有 Google API 2.3.3 的模拟器。但是，当我尝试来自具有 Android ICS 4.0 的 Galaxy SII 和具有 Google API 4.0 的模拟器的完全相同的链接时，在这两种情况下，quotes.csv 文件都只包含“缺失符号列表”。
在四处挖掘之后，我发现如果没有找到费率，可能会发生这种反应。但此响应适用于我在 Android 4.0（Galaxy SII 或模拟器）下尝试的任何货币。因此，我无法获得 Android 4.0 的费率，但我可以使用 Android 2.x。
有没有人遇到过同样的问题？有什么解决方法吗？
编辑：这是处理从雅虎货币服务下载率的线程代码：
//show the progress dialog
downloadingDialog.show();
Runnable getRates = new Runnable() {
public void run(){
dataNotFound = false;
final String baseDir = getApplicationContext().getFilesDir().getAbsolutePath();
//download the rates from yahoo to a CSV file
downloadFileViaHTTP (baseDir);
//read the file line
String filePath = baseDir + "/" + "quotes.csv";
Log.d(tag, "-> filePath = " + filePath);
try {
// open the file for reading
InputStream instream = new FileInputStream(filePath);
// if file the available for reading
if (instream != null) {
// prepare the file for reading
InputStreamReader inputreader = new InputStreamReader(instream);
BufferedReader buffreader = new BufferedReader(inputreader);
//read the line
String fileLine = buffreader.readLine();
Log.d(tag, "fileLine = " + fileLine);
instream.close();
}
}
catch (Exception ex) {
// print stack trace.
}
}
};
final Thread t = new Thread(getRates);
t.start();
这是我从雅虎网站下载quotes.csv 文件的功能：
public void downloadFileViaHTTP (String localPath) {
Log.d(tag, "downloadFileViaHTTP...");
try {
//this is the Yahoo url
String urlFile = "http://download.finance.yahoo.com/d/quotes.csv?s=" + fromCurrency + toCurrency + "=X&f=sl1d1t1ba&e=.csv";
Log.d(tag,"urlFile = " + urlFile);
URL url = new URL(urlFile);
//create the new connection
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.connect();
//pointer to the downloaded file path
String localFileName = localPath + "/" + "quotes.csv";
//this is the actual downloaded file
File MyFilePtrDest = new File(localFileName);
Log.d(tag,"localFileName = " + localFileName);
//this will be used in reading the data from the Internet
InputStream inputStream = urlConnection.getInputStream();
//this will be used to write the downloaded data into the file we created
FileOutputStream fileOutput = new FileOutputStream(MyFilePtrDest);
byte[] buffer = new byte[1024];
int bufferLength = 0; //used to store a temporary size of the buffer
//write buffer contents to file
while ((bufferLength = inputStream.read(buffer)) > 0 ) {
//add the data in the buffer to the file in the file output stream (the file on the sd card
fileOutput.write(buffer, 0, bufferLength);
}
inputStream.close();
//close the output stream when done
fileOutput.flush();
fileOutput.close();
urlConnection.disconnect();
}
catch (IOException e) {
//data were not found
dataNotFound = true;
// TODO Auto-generated catch block
e.printStackTrace();
}
}
这是来自 Google API 2.3.3 模拟器的日志：
12-18 11:04:24.091: D/CurrencyConverter(414): downloadFileViaHTTP...
12-18 11:04:24.091: D/CurrencyConverter(414): urlFile = http://download.finance.yahoo.com/d/quotes.csv?s=EURUSD=X&f=sl1d1t1ba&e=.csv
12-18 11:04:24.282: D/CurrencyConverter(414): localFileName = /data/data/com.myapps.currencyconverter/files/quotes.csv
12-18 11:04:24.461: D/CurrencyConverter(414): -> filePath = /data/data/com.myapps.currencyconverter/files/quotes.csv
12-18 11:04:24.461: D/CurrencyConverter(414): fileLine = "EURUSD=X",1.3172,"12/18/2012","4:03am",1.317,1.3174
这是来自 Google API 4.0 模拟器的日志：
12-18 11:47:36.130: D/CurrencyConverter(668): downloadFileViaHTTP...
12-18 11:47:36.130: D/CurrencyConverter(668): urlFile = http://download.finance.yahoo.com/d/quotes.csv?s=EURUSD=X&f=sl1d1t1ba&e=.csv
12-18 11:47:36.449: D/dalvikvm(668): GC_CONCURRENT freed 306K, 4% free 11714K/12167K, paused 5ms+10ms
12-18 11:47:36.951: D/CurrencyConverter(668): localFileName = /data/data/com.myapps.currencyconverter/files/quotes.csv
12-18 11:47:37.159: D/CurrencyConverter(668): -> filePath = /data/data/com.myapps.currencyconverter/files/quotes.csv
12-18 11:47:37.159: D/CurrencyConverter(668): fileLine = Missing Symbols List.
正如您所看到的“fileLine”字符串变量，在第一种情况下，它获得了正确的汇率，而在第二种情况下，quotes.csv 文件仅包含“缺失符号列表”。价值。
EDIT2：我已经将完整的Android项目上传到一个共享文件夹，所以大家可以试试。您可以使用 Android 2.x 和 4 模拟器（或手机，如果您有 :-)）编译和运行
EDIT3：虽然这不是一个直接的答案，但它仍然是一种解决方法。我使用谷歌货币计算器而不是雅虎。要使用 Google 货币计算器，只需将 Yahoo 网址更改为以下网址：http ://www.google.com/ig/calculator?hl=en&q=1 " + fromCurrency + "=?" + toCurrency。点击此链接到看一个将 78 欧元兑换成美元的例子。我检查了一下，它适用于两个 Android 版本。但是，如果有人发现雅虎网站发生这种情况的原因，最好与我们分享。