任何人都可以知道如何使用Streams读取位于sdcard
的二进制文件,如Inputstream
,CountingInputStream
或SwappedDataInputStream
?
我正在使用这三个流来读取当前在Resources folder
中的文件,但现在我想在sdcard
中移动该文件,但我无法更改这些流,因为我已经做了很多工作而且我无法回滚我的工作。
我是这样做的,但它给了我FileNotFoundException
。我需要你的帮助。
AssetManager assetManager = getResources().getAssets();
final File folder = new File(Environment.getExternalStorageDirectory() + "/map");
boolean success = false;
if(!folder.exists()){
success = folder.mkdir();
} else {
Log.i("folder already exists", "folder already exists");
}
try {
iStream = assetManager.open(Environment.getExternalStorageDirectory().getAbsolutePath().concat("/map/map.amf"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
cis = new CountingInputStream(iStream);
input = new SwappedDataInputStream(cis);
非常感谢任何建议。
这是一个简单的方法,只是将输入流的内容复制到输出流:
/**
* Copy the content of the input stream into the output stream, using a
* temporary byte array buffer whose size is defined by
* {@link #IO_BUFFER_SIZE}.
*
* @param in
* The input stream to copy from.
* @param out
* The output stream to copy to.
*
* @throws java.io.IOException
* If any error occurs during the copy.
*/
public static void copy(InputStream in, OutputStream out)
throws IOException {
byte[] b = new byte[IO_BUFFER_SIZE];
int read;
while ((read = in.read(b)) != -1) {
out.write(b, 0, read);
}
}
它取自我之前制作的应用程序:http://code.google.com/p/meneameandroid/source/browse/trunk/src/com/dcg/util/IOUtilities.java
为了确保dir存在于您想要写入/读取数据的位置,我使用了以下内容:
/**
* Prepares the SDCard with all we need
*/
private void prepareSDCard() {
// Create app dir in SDCard if possible
File path = new File("/sdcard/MyAppDirectory/");
if(! path.isDirectory()) {
if ( path.mkdirs() )
{
Log.d(TAG,"Directory created: /sdcard/MyAppDirectory");
}
else
{
Log.w(TAG,"Failed to create directory: /sdcard/MyAppDirectory");
}
}
}
从SD卡写入/读取的权限是:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
编辑:链接已更新