读出指定文件夹下的文件，并写入文件

随便记录一下，直接上代码：

 private void listFile(File file) {
        if (!file.exists()) {
            Toast.makeText(this, "路径不存在!", Toast.LENGTH_SHORT).show();
            return;
        }
        if (file.isDirectory()) {

            File[] listFiles = file.listFiles();
            int id = 1;
            for (File fileItem : listFiles) {
                String itemName = fileItem.getName().substring(0, fileItem.getName().indexOf('.'));
                mDataLib.items.add(new DataLib.Item(id++, itemName, fileItem.getAbsolutePath()));
                Log.d(TAG, "fileItem = " + itemName + ",  path=" + fileItem.getAbsolutePath());

            }
            view_img.setImageURI(Uri.fromFile(new File(listFiles[0].getAbsolutePath())));//显示本地图片文件

            Gson gson = new Gson();

            Log.d(TAG, "==>" + gson.toJson(mDataLib));
            try {
                ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(myDb));
                oos.writeObject(mDataLib);
                oos.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        } else {
            Log.d(TAG, "filename = " + file.getName());
        }
    }

    private DataLib readObject() {
        Object obj = null;
        if (new File(myDb).exists()) {
            try {
                ObjectInputStream ois = new ObjectInputStream(new FileInputStream(myDb));
                obj = ois.readObject();
                ois.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        return (DataLib) obj;
    }