android保存文件到SD卡中

想把文件保存到SD卡中，一定要知道SD卡的路徑，有人說可以用File explore來查看，這種方法不太好，因為隨著android版本的升級，SD卡的路徑可能會發生改變。在1.6的時候SD的路徑是/sdCard。後續版本都改成了mnt/sdCard。所有還是使用API來獲取：

Environment.getExternalStorageDirectory()

//判斷SDcard是否存在並且可讀寫
				if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
					service.saveToSDCard(filename,filecontent);
					Toast.makeText(getApplicationContext(), R.string.success, 1).show();
				}else{
					Toast.makeText(getApplicationContext(), R.string.sdcarderror, 1).show();
				}

	/**
	 * 保存到SD卡
	 * @param filename
	 * @param filecontent
	 * @throws Exception
	 */
	public void saveToSDCard(String filename, String filecontent)throws Exception{
		File file = new File(Environment.getExternalStorageDirectory(),filename);
		FileOutputStream outStream = new FileOutputStream(file);
		outStream.write(filecontent.getBytes());
		outStream.close();
	}	

	@Override
		public void onClick(View v) {
			EditText filenameText = (EditText)findViewById(R.id.filename);
			EditText filecontentText = (EditText)findViewById(R.id.filecontent);
			String filename = filenameText.getText().toString();
			String filecontent = filecontentText.getText().toString();
			FileService service = new FileService(getApplicationContext());
			try {
				//判斷SDcard是否存在並且可讀寫
				if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
					service.saveToSDCard(filename,filecontent);
					Toast.makeText(getApplicationContext(), R.string.success, 1).show();
				}else{
					Toast.makeText(getApplicationContext(), R.string.sdcarderror, 1).show();
				}
				
			} catch (Exception e) {
				Toast.makeText(getApplicationContext(), R.string.fail, 1).show();
				e.printStackTrace();
			}
			Toast.makeText(getApplicationContext(), R.string.success, 1).show();
		}