定制旋转/下拉菜单 [英] Custom Spinners/drop down menu

问题描述

在应用程序Astrid Tasks中，有一个按钮。当您按下按钮时，会出现一个下拉菜单。

In the app Astrid Tasks, there is a button. When you press the button, a drop down menu comes up.

它基本上是一个微调器，但是以下拉列表形式。

It's basically a spinner but in a drop-down-list form.

有没有人知道怎么做类似的事情？这是一个小部件，我只是看不到？

Does anyone know how to do something similar? Is this a widget I just don't see?

推荐答案

作为这个的原始作者（我是主要的Astrid的Android开发人员）我很乐意分享Astrid的做法。我将在这里发布基础知识，但您可以在我们的github回购中找到更多详细信息（ https://github.com/ todoroo /阿斯特丽德）。基本思想是扩展GreenDroid的QuickActionWidget，如hanry所示。子类看起来像：

As the original author of this (I'm one of the primary Android developers for Astrid) I'd be happy to share how Astrid does it. I'll post the basics here, but you can find more details at our github repo (https://github.com/todoroo/astrid). The basic idea is to extend GreenDroid's QuickActionWidget as hanry suggests. The subclass looks something like:

public class MenuPopover extends QuickActionWidget {

    protected DisplayMetrics metrics;
    protected LinearLayout content;

    public MenuPopover(Context context) {
        super(context);
        setContentView(R.layout.my_layout);

        content = (LinearLayout) getContentView().findViewById(R.id.content);
        metrics = context.getResources().getDisplayMetrics();

        setFocusable(true);
        setTouchable(true);
    }

    @Override
    protected void populateQuickActions(List<QuickAction> quickActions) {
        // Do nothing
    }

    @Override
    protected void onMeasureAndLayout(Rect anchorRect, View contentView) {
        contentView.setLayoutParams(new     FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,     ViewGroup.LayoutParams.WRAP_CONTENT));
        contentView.measure(MeasureSpec.makeMeasureSpec(getScreenWidth(),     MeasureSpec.EXACTLY),
                ViewGroup.LayoutParams.WRAP_CONTENT);

        int rootHeight = contentView.getMeasuredHeight();

        int offsetY = getArrowOffsetY();
        int dyTop = anchorRect.top;
        int dyBottom = getScreenHeight() - anchorRect.bottom;

        boolean onTop = (dyTop > dyBottom);
        int popupY = (onTop) ? anchorRect.top - rootHeight + offsetY : anchorRect.bottom -  offsetY;

        setWidgetSpecs(popupY, onTop);
    }
}

布局文件my_layout.xml很简单： / p>

The layout file my_layout.xml is pretty simple:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">
    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingLeft="10dip">

        <LinearLayout
                android:id="@+id/content"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_below="@+id/gdi_arrow_up"
                android:orientation="vertical"/>

        <ImageView
            android:id="@+id/gdi_arrow_up"
            android:layout_width="27dip"
            android:layout_height="27dip"
            android:layout_marginLeft="-10dip"
            android:scaleType="fitCenter"
            android:layout_marginBottom="-8dip"
            android:src="?attr/asListArrowUp" />

        <ImageView
            android:id="@+id/gdi_arrow_down"
            android:layout_width="27dip"
            android:layout_height="27dip"
            android:scaleType="fitCenter"
            android:layout_marginBottom="-8dip"
            android:layout_below="@android:id/list"/>

        </RelativeLayout>
</FrameLayout>

然后，你可以添加一个简单的帮助方法到popover类来添加视图（即行，与可选的侦听器）到popO的主体：

Then, you can just add a simple helper method to the popover class to add views (i.e. rows, with optional listeners) to the main body of the popover:

public void addViewToContent(View v, OnClickListener listener) {
    content.addView(v);
    if (listener != null) {
        v.setOnClickListener(listener);
    }
}

创建弹出窗口的实例后，您可以显示它通过调用

After creating an instance of the popup, you can show it by calling

menuPopover.show(anchorView);

这是一个有点简化的版本 - 在实践中，我们附加了一些附加信息，监听器等。对这些观点，使他们实际上做点事时的事情。如果需要，可以在 https://github.com/todoroo/astrid 查看完整的代码 - 类是com.todoroo.astrid.ui.MainMenuPopover。

This is a somewhat simplified version -- in practice, we attach some addition information, listeners, etc. to those views to make them actually do things when clicked. If you want, you can check out the full code at https://github.com/todoroo/astrid -- the class is com.todoroo.astrid.ui.MainMenuPopover.

感谢您使用Astrid！

Thanks for using Astrid!

这篇关于定制旋转/下拉菜单的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！