Android - 将资产复制到内部存储

Question

美好的一天!

我刚开始为android开发.在我的应用程序中,我需要将assets资源文件夹中的项目复制到内部存储.

我在SO上搜索了很多,包括将其复制到外部存储器. 如何将文件从'assets'文件夹复制到SD卡？

这就是我想要实现的:我有一个目录已存在于内部存储中,如X> Y> Z. 我需要一个文件复制到Y,另一个文件复制到Z.

任何人都可以帮我解决代码片段吗？我真的不知道如何继续这个.

对不起,我的英语不好.

非常感谢.

Answer 1

使用

 String out= Environment.getExternalStorageDirectory().getAbsolutePath() + "/X/Y/Z/" ; 

        File outFile = new File(out, Filename);

在您的参考编辑后.链接答案.

private void copyAssets() {
    AssetManager assetManager = getAssets();
    String[] files = null;
try {
    files = assetManager.list("");
} catch (IOException e) {
    Log.e("tag", "Failed to get asset file list.", e);
  }
 for(String filename : files) {
    InputStream in = null;
    OutputStream out = null;
    try {
      in = assetManager.open(filename);

      String outDir = Environment.getExternalStorageDirectory().getAbsolutePath() + "/X/Y/Z/" ; 

      File outFile = new File(outDir, filename);

      out = new FileOutputStream(outFile);
      copyFile(in, out);
      in.close();
      in = null;
      out.flush();
      out.close();
        out = null;
      } catch(IOException e) {
          Log.e("tag", "Failed to copy asset file: " + filename, e);
         }       
       }
     }
     private void copyFile(InputStream in, OutputStream out) throws IOException {
        byte[] buffer = new byte[1024];
      int read;
     while((read = in.read(buffer)) != -1){
       out.write(buffer, 0, read);
     }
   }

Answer 2

这是我的 Kotlin 解决方案，具有可自动关闭的流以复制到内部应用程序存储中：

val copiedFile = File(context.filesDir, "copied_file.txt")
context.assets.open("original_file.txt").use { input ->
    copiedFile.outputStream().use { output ->
        input.copyTo(output, 1024)
    }
}

Answer 3

嗨,大家好,我做过这样的事.允许您复制所有目录结构以从Android AssetManager复制:)

public String copyDirorfileFromAssetManager(String arg_assetDir, String arg_destinationDir) throws IOException
{
    File sd_path = Environment.getExternalStorageDirectory(); 
    String dest_dir_path = sd_path + addLeadingSlash(arg_destinationDir);
    File dest_dir = new File(dest_dir_path);

    createDir(dest_dir);

    AssetManager asset_manager = getApplicationContext().getAssets();
    String[] files = asset_manager.list(arg_assetDir);

    for (int i = 0; i < files.length; i++)
    {

        String abs_asset_file_path = addTrailingSlash(arg_assetDir) + files[i];
        String sub_files[] = asset_manager.list(abs_asset_file_path);

        if (sub_files.length == 0)
        {
            // It is a file
            String dest_file_path = addTrailingSlash(dest_dir_path) + files[i];
            copyAssetFile(abs_asset_file_path, dest_file_path);
        } else
        {
            // It is a sub directory
            copyDirorfileFromAssetManager(abs_asset_file_path, addTrailingSlash(arg_destinationDir) + files[i]);
        }
    }

    return dest_dir_path;
}


public void copyAssetFile(String assetFilePath, String destinationFilePath) throws IOException
{
    InputStream in = getApplicationContext().getAssets().open(assetFilePath);
    OutputStream out = new FileOutputStream(destinationFilePath);

    byte[] buf = new byte[1024];
    int len;
    while ((len = in.read(buf)) > 0)
        out.write(buf, 0, len);
    in.close();
    out.close();
}

public String addTrailingSlash(String path)
{
    if (path.charAt(path.length() - 1) != '/')
    {
        path += "/";
    }
    return path;
}

public String addLeadingSlash(String path)
{
    if (path.charAt(0) != '/')
    {
        path = "/" + path;
    }
    return path;
}

public void createDir(File dir) throws IOException
{
    if (dir.exists())
    {
        if (!dir.isDirectory())
        {
            throw new IOException("Can't create directory, a file is in the way");
        }
    } else
    {
        dir.mkdirs();
        if (!dir.isDirectory())
        {
            throw new IOException("Unable to create directory");
        }
    }
}

Answer 4

试试下面的代码

private void copyAssets() {
    AssetManager assetManager = getAssets();
    String[] files = null;
    try {
        files = assetManager.list("");
    } catch (IOException e) {
        Log.e("tag", "Failed to get asset file list.", e);
    }
    for(String filename : files) {
        InputStream in = null;
        OutputStream out = null;
        try {
          in = assetManager.open(filename);
          File outFile = new File(getExternalFilesDir(null), filename);
          out = new FileOutputStream(outFile);
          copyFile(in, out);
          in.close();
          in = null;
          out.flush();
          out.close();
          out = null;
        } catch(IOException e) {
            Log.e("tag", "Failed to copy asset file: " + filename, e);
        }       
    }
}
private void copyFile(InputStream in, OutputStream out) throws IOException {
    byte[] buffer = new byte[1024];
    int read;
    while((read = in.read(buffer)) != -1){
      out.write(buffer, 0, read);
    }
}

Answer 5

我在 Kotlin 上的小解决方案，用于将数据从资产复制到内部存储

fun copy() {
    val bufferSize = 1024
    val assetManager = context.assets
    val assetFiles = assetManager.list("")

    assetFiles.forEach {
        val inputStream = assetManager.open(it)
        val outputStream = FileOutputStream(File(context.filesDir, it))

        try {
            inputStream.copyTo(outputStream, bufferSize)
        } finally {
            inputStream.close()
            outputStream.flush()
            outputStream.close()
        }
    }
}