编程显示动作条上溢 [英] Programmatically display actionbar overflow

问题描述

我有一个菜单的动作条。当您单击按钮，菜单显示出来，一切都很好与世界同步。

I have an actionbar with a menu. When you click the button, the menu shows up and all is well with the world.

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
    <item android:id="@+id/reload" 
        android:title="@string/reload" 
        android:alphabeticShortcut="r" 
        android:numericShortcut="1" 
        android:titleCondensed="Rload"></item>

    <group android:id="@+id/adv" android:menuCategory="secondary">
        ...options
    </group>
</menu>

不过，我刚告知，我们有一个客户，其设备具有某种被显示在当前，使他们不能访问菜单等菜单栏。所以我增加了一个按钮上的WebView与javascriptinterface告诉我的活动以编程方式显示菜单。我能到那里就好了，但我不能为我的生活弄清楚如何显示菜单，如果菜单按钮为pressed。

However, I just got told that we have a client whose device has some sort of other menu bar that is displayed over the current one so they can't access the menu. So I added a button on the webview with a javascriptinterface to tell my Activity to display the menu programmatically. I can get there just fine, but I can't for the life of me figure out how to display the menu as if the menu button was pressed.

我试图做这样的事情：

private void showMenu() {
    try{
        actionbar.show();
        MenuItem menu = (MenuItem) findViewById(R.id.adv);
        menu.expandActionView();
    }
    catch(Exception e){
        Log.e(LOG_CAT,"Unable to inflate menu");
    }
}

但我得到一个空指针异常

but I'm getting a null pointer exception

java.lang.NullPointerException: Attempt to invoke interface method 'boolean android.view.MenuItem.expandActionView()' on a null object reference

这似乎是我想要做的应该是很轻松的，但它可能是我只是在做一些愚蠢的，而不是。

It seems like what I'm trying to do should be trivially easy, but it may be that I'm just doing something boneheaded instead.

修改我真的不希望只是显示R.id.adv，我想显示整个菜单，这样也许应该是 findViewById（R.menu .menu_main）来代替，其中 menu_main 是上面的XML中定义的文件的名称。

EDIT I don't actually want to just show R.id.adv, I would like to show the whole menu so that should probably be findViewById(R.menu.menu_main) instead, where menu_main is the name of the file that the above xml is defined in.

推荐答案

findViewById 看在活动中，没有菜单的视图层次。你需要得到你需要正确后，创建了菜单中的项目：

findViewById looks in the view hierarchy of the activity, not the menu. You need to get the items you need right after your menu is created:

编辑：

没想到这是可能的，但它是。随着这个答案这里是你如何能做到这一点：

Didn't think it's possible but it is. With the help of this answer here's how you can do it:

View mOverflow;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final View decor = getWindow().getDecorView();
    decor.post(new Runnable() {
        @Override
        public void run() {
            ArrayList<View> results = new ArrayList<>();
            decor.findViewsWithText(results, "OVERFLOW",
                    View.FIND_VIEWS_WITH_CONTENT_DESCRIPTION);

            if (results.size() == 1) {
                mOverflow = results.get(0);
            }
        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

private void showMenu() {
    actionbar.show();
    mOverflow.performClick();
}

而在你的 styles.xml ：

<style name="AppTheme" parent="android:Theme.Holo">
    <item name="android:actionOverflowButtonStyle">@style/Widget.ActionButton.Overflow</item>
</style>

<style name="Widget.ActionButton.Overflow" parent="@android:style/Widget.Holo.ActionButton.Overflow">
    <item name="android:contentDescription">OVERFLOW</item>
</style>

findViewsWithText 要求API 14+，但是答案我联系，具有更低的API的解决方案。

findViewsWithText requires API 14+, however the answer I linked, has a solution for lower APIs.

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