文件保存在安卓上

Question

我正在制作一个xml文件并将其保存在我的设备上 代码如下

HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://xx:xx:xx:xx:yy/LoginAndroid.asmx/login");
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        HttpResponse response = httpclient.execute(httppost);
        String responseBody = EntityUtils.toString(response.getEntity());
        //Toast.makeText( getApplicationContext(),"responseBody:   "+responseBody,Toast.LENGTH_SHORT).show();
        //saving the file as a xml
        FileOutputStream fOut = openFileOutput("loginData.xml",MODE_WORLD_READABLE);
        OutputStreamWriter osw = new OutputStreamWriter(fOut);
        osw.write(responseBody);
        osw.flush();
        osw.close();
        //reading the file as xml
        FileInputStream fIn = openFileInput("loginData.xml");
        InputStreamReader isr = new InputStreamReader(fIn);
        char[] inputBuffer = new char[responseBody.length()];
        isr.read(inputBuffer);
        String readString = new String(inputBuffer);

FIle 正在保存我也可以读取文件 一切都没问题，但看看这一行

char[] inputBuffer = new char[responseBody.length()];

它正在计算在保存文件时保存的字符串长度。我正在将文件保存在一个 Acivity 中并从另一个活动中读取它，我的应用程序将在本地保存文件一次，所以我无法每次都获取该返回字符串的长度 那么有没有办法动态分配char[] inputBuffer的大小？

Answer 1

您可以在另一个活动中使用以下代码来读取文件。看看 BufferedReader 类。

InputStream instream = new FileInputStream("loginData.xml");
// if file the available for reading
if (instream != null) {
  // prepare the file for reading
  InputStreamReader inputreader = new InputStreamReader(instream);
  BufferedReader buffreader = new BufferedReader(inputreader);
  String line;
  // read every line of the file into the line-variable, on line at the time
  while (buffreader.hasNext()) {
     line = buffreader.readLine();
    // do something with the line 
  }
}

编辑：

上面的代码对于读取文件工作正常，但是如果您只想分配char[] inputBuffer dynamicall的大小，则可以使用以下代码。

InputStream is = mContext.openFileInput("loginData.xml");
ByteArrayOutputStream bos = new ByteArrayOutputStream();
byte[] b = new byte[1024];
while ((int bytesRead = is.read(b)) != -1) {
   bos.write(b, 0, bytesRead);
}
byte[] inputBuffer = bos.toByteArray();

现在，根据需要使用inputBuffer。