如何以编程方式将文件复制到另一个目录？

Question

有一个image file内部的directory.怎么把copy这个image file变成directory刚刚创建的另一个？这两个directories是相同internal storage的设备:)

Answer 1

您可以使用这些功能.如果传入文件,第一个将复制包含所有子项的整个目录或单个文件.第二个仅对文件有用,并在第一个文件中调用每个文件.

另请注意,您需要具有执行此操作的权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />  

功能:

 public static void copyFileOrDirectory(String srcDir, String dstDir) {

        try {
            File src = new File(srcDir);
            File dst = new File(dstDir, src.getName());

            if (src.isDirectory()) {

                String files[] = src.list();
                int filesLength = files.length;
                for (int i = 0; i < filesLength; i++) {
                    String src1 = (new File(src, files[i]).getPath());
                    String dst1 = dst.getPath();
                    copyFileOrDirectory(src1, dst1);

                }
            } else {
                copyFile(src, dst);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void copyFile(File sourceFile, File destFile) throws IOException {
        if (!destFile.getParentFile().exists())
            destFile.getParentFile().mkdirs();

        if (!destFile.exists()) {
            destFile.createNewFile();
        }

        FileChannel source = null;
        FileChannel destination = null;

        try {
            source = new FileInputStream(sourceFile).getChannel();
            destination = new FileOutputStream(destFile).getChannel();
            destination.transferFrom(source, 0, source.size());
        } finally {
            if (source != null) {
                source.close();
            }
            if (destination != null) {
                destination.close();
            }
        }
    }

Answer 2

如果要以编程方式复制图像,请使用以下代码.

     File sourceLocation= new File (sourcepath);
     File targetLocation= new File (targetpath);

     InputStream in = new FileInputStream(sourceLocation);
            OutputStream out = new FileOutputStream(targetLocation);

            // Copy the bits from instream to outstream
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
            in.close();
            out.close();