Android SD卡文件读写-优快云博客

本文介绍了一个简单的Android应用程序如何实现从互联网获取数据并写入SD卡，以及如何从SD卡中读取这些数据进行解析展示的过程。文章通过具体代码示例展示了文件操作的基本流程，包括创建文件、写入数据、读取数据并解析为特定对象。

            private void writeDataFromInternet(String str) {

                try {
                    File file = new File(Environment.getExternalStorageDirectory(), "cache.txt");

                    if (!file.exists()){
                        file.createNewFile();
                    }
                    OutputStream fos = new FileOutputStream(file);

                    fos.write(str.getBytes());
                    Log.i("=====", "writeDataFromInternet: "+str);
                   fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }


            //判断sdcard卡是否挂载
            public  boolean isSdCardExist() {
                Log.e("=====", "isSdCardExist: ");
                return Environment.getExternalStorageState().equals(
                        Environment.MEDIA_MOUNTED);
            }

//读取

      //读取sdcard文件
      private void readFileFromSdcard(){
         try {
              File file = new File(Environment.getExternalStorageDirectory(),
             "cache.txt");
             FileInputStream is = new FileInputStream(file);
            byte[] b = new byte[is.available()];
            is.read(b);
            String result = new String(b);
            System.out.println("读取成功："+result);

              Gson  gson=new Gson();
            ComicBean comicBean = gson.fromJson(result, ComicBean.class);
            Log.e("=====", "readFileFromSdcard: "+comicBean.getData().getComics().get(0).getTitle());
            GridLayoutManager manager = new GridLayoutManager(getContext(), 3);
            rv.setLayoutManager(manager);

            MyRecyclerViewAdapter adapter = new MyRecyclerViewAdapter(getContext());
            adapter.setData(comicBean.getData().getComics());
            rv.setAdapter(adapter);
            adapter.notifyDataSetChanged();


        } catch (Exception e) {
            e.printStackTrace();
        }
    }