# Android自助餐之文件存儲
- [Android自助餐之文件存儲](#)
- [保存到應用目錄下](#)
- [保存到SD卡](#)
- [獲取SD卡大小](#)
- [獲取內部存儲空間](#)
### 保存到應用目錄下
~~~
//寫
FIle file = new File(context.getFilesDir(),"test.txt");//context.getCacheDir();為應用目錄下的緩存目錄
FileOutputStream fos=new FileOutputStream(file);
fos.write("test".getBytes());
fos.close();
//讀
FileInputStream fis = new FileInputStream(file);
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
String str=br.readLine();
~~~
### 保存到SD卡
聲明權限
~~~
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
~~~
獲取SD卡狀態
~~~
//判斷SD卡狀態
String state= Environment.getExternalStorageState();
if(state.equals(Environment.MEDAI_MOUNTED)){
//操作文件
File file = new File(Environment.getExteralStorageDirectory(),"test.txt");
}
~~~
### 獲取SD卡大小
~~~
File path = Environment.getExternalStorageDirectory();
StatFs stat = new StatFs(path.getPath());
long blockSize=stat.getBlockSize();//獲取塊大小
long totalBlocks=stats.getBlockCount();//獲取總塊數
long availableBlocks=stats.getAvailableBlocks();//獲取可用塊數
//計算大小
long totalSize= blockSize*totalBlocks;
long availSize=availableBlocks*totalBlocks;
//格式化字符串
String totalStr=Formatter.formatFileSize(context,totalSize);
String availStr=Formatter.formatFileSize(context,availSize);
~~~
### 獲取內部存儲空間
只需將上述代碼中`Environment.getExternalStorageDirectory()`改為`Environment.getDataDirectory()`
