Android SD卡文件存儲

Android SD卡文件存儲
1、在AndroidManifest清單文件中要對SD卡讀取進行支持
<!-- 在SDCard中創建與刪除文件權限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<!-- 往SDCard寫入數據權限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

2、文件讀寫
 private String read() {
        // 如果手機插入了SD卡，而且應用程序具有訪問SD的權限
         
        try {
            if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
                // 獲取SD卡的目錄
                File sdDirFile = Environment.getExternalStorageDirectory();
                //獲取指定文件對應的輸入流
                FileInputStream fis = new FileInputStream(sdDirFile.getCanonicalPath()+ FILE);
                //將指定輸入流包裝成BufferedReader
                BufferedReader br = new BufferedReader(new InputStreamReader(fis));
                 
                StringBuilder sb = new StringBuilder("");
                String line = null;
                while ((line =br.readLine())!=null) {
                    sb.append(line);
                }
                return sb.toString();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
 
    private void write(String context){
        try {
            if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
                File sdDir = Environment.getExternalStorageDirectory();
                File targetFile = new File(sdDir.getCanonicalPath()+ FILE);
                RandomAccessFile raf = new RandomAccessFile(targetFile, "rw");
                raf.seek(targetFile.length());
                raf.write(context.getBytes());
                raf.close();
            }
        } catch (Exception e) {
        }
    }