android - 微调器 : get state or get notified when opens

Question

是否有可能知道 Spinner 是打开还是关闭？如果 Spinner 有某种 onOpenListener 就更好了。

我尝试过像这样使用 OnItemSelectedListener:

spinnerType.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            executeSomething();

        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
            Log.d("nothing" , "selected");  
        }

    });

我知道如果选择了某些东西(在 executeSomething() 中)，窗口将关闭。但是如果我在对话框之外单击，我不会收到通知，这也会关闭微调器

Answer 1

监视这些事件的另一个选项是扩展 Spinner 类并使用其方法之一(performClick() 将触发其对话框/弹出窗口)，然后是监视持有此自定义 Spinner 的窗口的焦点。这应该为您提供所有可能的完成可能性(对于对话框或下拉模式)所需的关闭事件。

自定义Spinner类:

public class CustomSpinner extends Spinner {

   /**
    * An interface which a client of this Spinner could use to receive
    * open/closed events for this Spinner. 
    */
    public interface OnSpinnerEventsListener {

        /**
         * Callback triggered when the spinner was opened.
         */
         void onSpinnerOpened(Spinner spinner);

        /**
         * Callback triggered when the spinner was closed.
         */
         void onSpinnerClosed(Spinner spinner);

    }

    private OnSpinnerEventsListener mListener;
    private boolean mOpenInitiated = false;

    // implement the Spinner constructors that you need

    @Override
    public boolean performClick() {
        // register that the Spinner was opened so we have a status
        // indicator for when the container holding this Spinner may lose focus
        mOpenInitiated = true;
        if (mListener != null) {
            mListener.onSpinnerOpened(this);
        }
        return super.performClick();
    }

    @Override
    public void onWindowFocusChanged (boolean hasFocus) {
        if (hasBeenOpened() && hasFocus) {
            performClosedEvent();
        }
    }

    /**
    * Register the listener which will listen for events.
    */
    public void setSpinnerEventsListener(
            OnSpinnerEventsListener onSpinnerEventsListener) {
        mListener = onSpinnerEventsListener;
    }

    /**
     * Propagate the closed Spinner event to the listener from outside if needed.
     */
    public void performClosedEvent() {
        mOpenInitiated = false;
        if (mListener != null) {
            mListener.onSpinnerClosed(this);
        }
    }

    /**
     * A boolean flag indicating that the Spinner triggered an open event.
     * 
     * @return true for opened Spinner 
     */
    public boolean hasBeenOpened() {
        return mOpenInitiated;
    }

}