Question

我已经实现了一个扩展BaseAdapter的自定义微调器，并且我已经覆盖了getView()和getDropDownView()，以便为微调器和下拉项提供不同的视图。

如何在打开或关闭微调器的下拉视图时收到通知？

我的自定义微调器类是这样的：

public class CustomSpinnerAdapter extends ArrayAdapter<String> {

@Override
public View getView(int i, View view, ViewGroup viewGroup) {

}

@Override
public View getDropDownView(int position, View convertView, ViewGroup parent){

}

Answer 1

在自定义微调器上添加打开和关闭侦听器

    import android.content.Context;
    import android.util.AttributeSet;
    import android.widget.Spinner;

    public class CustomSpinner extends Spinner {
    // private static final String TAG = "CustomSpinner";
    private OnSpinnerEventsListener mListener;
    private boolean mOpenInitiated = false;

    public CustomSpinner(Context context, AttributeSet attrs, int defStyleAttr, int mode) {
        super(context, attrs, defStyleAttr, mode);
    }

    public CustomSpinner(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public CustomSpinner(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomSpinner(Context context, int mode) {
        super(context, mode);
    }

    public CustomSpinner(Context context) {
        super(context);
    }

    public interface OnSpinnerEventsListener {

        void onSpinnerOpened(Spinner spin);

        void onSpinnerClosed(Spinner spin);

    }

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

    public void setSpinnerEventsListener(OnSpinnerEventsListener onSpinnerEventsListener) {
        mListener = onSpinnerEventsListener;
    }

    /**
     * Propagate the closed Spinner event to the listener from outside.
     */
    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;
    }

    @Override
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        super.onWindowFocusChanged(hasWindowFocus);
        if (hasBeenOpened() && hasWindowFocus) {
            performClosedEvent();
        }
    }
}

Answer 2

对于微调器的自定义视图，我们必须构建自定义适配器类。
所有事件，侦听器等。微调器的默认方法在自定义微调器视图上的工作方式相同。

因此，您可以在ItemSelectedListener方法中实现用于打开/关闭微调器的代码。

mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            ...
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) { }
    });

自定义微调器下拉视图监听器

2 个答案: