android - 如何复用 getExternalStorageState？

Question

如何将其写在自己的类中以便反复使用？在注释行“//加载列表”所在的位置，我需要能够在运行时更改它。

提前收到信息。

/**
 * -- Check to See if the SD Card is Mounted & Loads the Ordered List
 * ======================================================================
 **/
private void storageState() {
    if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_MOUNTED)) {

        orderASC();// Loads the list

    } else if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_UNMOUNTED)) {
        Alerts.sdCardMissing(this);
    }
}

修订:

class StorageStateChecker  {
  static void storageState(Activity param, Listener l) {
    if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_MOUNTED)) {

        l.orderASC_Label();//Load the list by Label ASC
        l.orderDSC_Label();
        l.orderASC_Title();//Load the list by Title ASC
        l.orderDSC_Title();

    } else if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_UNMOUNTED)) {

            // Pass context to AlertDialog.Builder
            AlertDialog alertDialog = new AlertDialog.Builder(null).create();
            alertDialog.setTitle("External Storage State");
            alertDialog.setMessage("Your SD-Card is not mounted!  If the device is plugged into a computer via the USB, please disconect the device.");
            alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    //this.finish();
                }
            });
            // alertDialog.setIcon(R.drawable.icon);
            alertDialog.show();
    }
  }

public interface Listener {
    public void orderASC_Label();
    public void orderDSC_Label();
    public void orderASC_Title();
    public void orderDSC_Title();
  }
}

Answer 1

我会这样做:

public static boolean performExternalStorageOperation(Runnable doIfMounted) {
    if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_MOUNTED)) {

        orderASC();// Loads the list
        if(doIfMounted != null) {
            doIfMounted.run();
        }
        return true;
    } else if (android.os.Environment.getExternalStorageState().equals(
            android.os.Environment.MEDIA_UNMOUNTED)) {
        Alerts.sdCardMissing(this);
    }
    return false;
}

您可以将 Runnable 替换为任何类型的通用 Listener(我经常使用 OnClickListeners 来处理不一定是点击的操作)，或者编写您自己的回调类并使用通用的调用方法，但这是我的一般方法。