问题记录-PopupWindow的setOnDismissListener失效问题

公司项目里有一个列表弹窗的需求，就自定义了个PoppupWindow，弹出从底部平移动画弹出，并且弹窗高度固定（因为可能有很多条数据，如果MatchParent会很丑）。在弹窗show的时候,我给整个window设置了个0.5的透明度，然后弹窗消失的时候再设置回来，本来想着在setOnDismissListener的回调方法里添加设置回来的操作，但回调不起作用。最后想了想，直接重写了PopupWindow的dismiss()方法，在该方法里添加设置回来的操作，即可，下面是大致的代码逻辑：

public class TestPopupWindow extends PopupWindow {

    private LinearLayout mLlTitle;
    private TextView mTvTitle;
    private ListView mLvData;
    private QualityPopupAdapter mAdapter;
    private OnClickItemListener listener;
    private Context mContext;

    public void setListener(OnClickItemListener listener) {
        this.listener = listener;
    }

    public TestPopupWindow(final Context context) {
        mContext = context;
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.qm_popupwindow_list, null);

        setContentView(view);

        setWidth(ViewGroup.LayoutParams.MATCH_PARENT);
        setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);
        setFocusable(true);
        setOutsideTouchable(true);
        update();
        setBackgroundDrawable(new ColorDrawable(0000000000));
        //设置弹入弹出动画
        setAnimationStyle(R.style.qm_style_popup_window);
    }

    @Override
    public void dismiss() {
        super.dismiss();
        setBackgroundAlpha(1.0f);
    }

    /**
     * 显示
     *
     * @param view
     */
    public void show(View view) {
        if (isShowing()) {
            dismiss();
        } else {
            setBackgroundAlpha(0.5f);
            showAtLocation(view, Gravity.BOTTOM, 0, 0);
        }
    }

    /**
     * 改变背景透明度
     *
     * @param alpha
     */
    private void setBackgroundAlpha(float alpha) {
        WindowManager.LayoutParams layoutParams = ((Activity)      
            mContext).getWindow().getAttributes();
        layoutParams.alpha = alpha;
        ((Activity) mContext).getWindow().setAttributes(layoutParams);
    }
 }