Android動态申請SDcard權限

Android6.0後必須使用動态申請SDcard權限，否則會抛出"java.io.FileNotFoundException"異常。

try {
    //檢測是否有寫的權限
    int permission = ActivityCompat.checkSelfPermission(this,
            "android.permission.WRITE_EXTERNAL_STORAGE");
    if (permission != PackageManager.PERMISSION_GRANTED) {
        // 沒有寫的權限，去申請寫的權限，會彈出對話框
        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
    }
} catch (Exception e) {
    e.printStackTrace();
}