標籤:sdc roi ted equal 應該 sdcard color write ges
1.向sdcard中寫入資料:
發現向/mnt/sdcard路徑寫資料會報錯,原因:沒有開啟相應許可權
解決:設定檔中加入
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
或者:
另外:不建議寫入程式碼寫成:/mnt/sdcard,應該這樣寫:
String sdPath = Environment.getExternalStorageDirectory().getPath();
在儲存資料到sdcard之前,還應該判斷下是否存在sdcard:
if (Environment.MEDIA_MOUNTED.equals(Environment .getExternalStorageState())) { String sdPath = Environment.getExternalStorageDirectory() .getPath(); // ...... } else { Toast.makeText(getApplicationContext(), "sd卡不可用", Toast.LENGTH_LONG).show(); }
2.擷取sdcard總大小和可用空間:
File file = Environment.getExternalStorageDirectory(); //總大小 long totalSpace = file.getTotalSpace(); //可用大小 long usableSpace = file.getUsableSpace(); //注意返回格式是位元組,轉換 String formatTotalSpace = Formatter.formatFileSize(MainActivity.this, totalSpace); String formatUsableSpace = Formatter.formatFileSize(MainActivity.this, usableSpace);
安卓開發:sd卡操作