java - 有没有快速将文件复制到 sdcard 的方法

Question

我具有将存储在资产中的 jpeg 复制到 SD 卡的功能。它有效，但非常非常慢。平均文件大小约为 600k 。有没有更好的方法来做到这一点，代码：

void SaveImage(String from, String to) throws IOException {
  // opne file from asset
  AssetManager assetManager = getAssets();
  InputStream inputStream;
  try {
    inputStream = assetManager.open(from);
  } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    return;
  }

  // Open file in sd card
  String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
  OutputStream outStream = null;
  File file = new File(extStorageDirectory, to);
  try {
    outStream = new FileOutputStream(file);
  } catch (FileNotFoundException e) {
    e.printStackTrace();
    return;
  }

  int c;
  while ((c = inputStream.read()) != -1) {
    outStream.write(c);
  }

  outStream.close();
  inputStream.close();
  return;
}

Answer 1

一次读取和写入多个字符。16KB 可能是一个合理的缓冲区大小，尽管您可以随意尝试。

Answer 2

您应该尝试使用Buffer ClassesBufferedInputStream和BufferedOutputStream

InputStream inputStream;
BufferedInputStream bis;
try {
    inputStream = assetManager.open(from);
    bis = new BufferedInputStream(inputStream);
} catch (IOException e) {
...
...
try {
    outStream = new BufferedOutputStream(new FileOutputStream(file));
} catch (FileNotFoundException e) {
...
...
    while ((c = bis.read()) != -1) {
    ...
    }
...
...

bis.close();

祝你好运