如何隐藏操作栏中的菜单项？

本文翻译自：How do I hide a menu item in the actionbar?

I have an action bar with a menuitem. 我有一个带有menuitem的操作栏。 How can I hide/show that menu item? 如何隐藏/显示该菜单项？

This is what I'm trying to do: 这就是我想要做的：

MenuItem item = (MenuItem) findViewById(R.id.addAction);
item.setVisible(false);
this.invalidateOptionsMenu();

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#1楼

参考：https://stackoom.com/question/irfn/如何隐藏操作栏中的菜单项

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#2楼

Get a MenuItem pointing to such item, call setVisible on it to adjust its visibility and then call invalidateOptionsMenu() on your activity so the ActionBar menu is adjusted accordingly. 获取指向此项目的MenuItem ，调用其上的setVisible以调整其可见性，然后在您的活动上调用invalidateOptionsMenu() ，以便相应地调整ActionBar菜单。

Update: A MenuItem is not a regular view that's part of your layout. 更新： MenuItem不是布局的常规视图。 Its something special, completely different. 它的特殊之处，完全不同。 Your code returns null for item and that's causing the crash. 您的代码为item返回null ，这导致崩溃。 What you need instead is to do: 你需要做的是：

MenuItem item = menu.findItem(R.id.addAction);

Here is the sequence in which you should call: first call invalidateOptionsMenu() and then inside onCreateOptionsMenu(Menu) obtain a reference to the MenuItem (by calling menu.findItem() ) and call setVisible() on it 下面是你应该调用的序列：首先调用invalidateOptionsMenu()然后在onCreateOptionsMenu(Menu)里面获取对MenuItem的引用（通过调用menu.findItem() ）并在其上调用setVisible()

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#3楼

You can call this: 你可以这样称呼：

MenuItem item = menu.findItem(R.id.my_item);
item.setVisible(false);

Update: 更新：

Make sure your code doesn't returns null for item or it may crash the application. 确保您的代码不会为item返回null ，否则可能会导致应用程序崩溃。

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#4楼

Yes. 是。

1. You can set a flag/condition. 您可以设置标志/条件。
2. Call invalidateOptionsMenu() when you want to hide the option. 如果要隐藏选项，请调用invalidateOptionsMenu() 。 This will call onCreateOptionsMenu() . 这将调用onCreateOptionsMenu() 。
3. In onCreateOptionsMenu() , check for the flag/condition and show or hide it the following way: 在onCreateOptionsMenu() ，检查标志/条件并以下列方式显示或隐藏它：

 MenuItem item = menu.findItem(R.id.menu_Done); if (flag/condition)) { item.setVisible(false); } else { } 

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#5楼

Found an addendum to this question: 找到这个问题的附录：

If you want to change the visibility of your menu items on the go you just need to set a member variable in your activity to remember that you want to hide the menu and call invalidateOptionsMenu() and hide the items in your overridden onCreateOptionsMenu(...) method. 如果您想在旅途中更改菜单项的可见性，您只需在活动中设置一个成员变量，以便记住您要隐藏菜单并调用invalidateOptionsMenu()并隐藏被覆盖的onCreateOptionsMenu(...)的项目onCreateOptionsMenu(...)方法。

//anywhere in your code
...
mState = HIDE_MENU; // setting state
invalidateOptionsMenu(); // now onCreateOptionsMenu(...) is called again
...

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    // inflate menu from xml
    MenuInflater inflater = getSupportMenuInflater();
    inflater.inflate(R.menu.settings, menu);

    if (mState == HIDE_MENU)
    {
        for (int i = 0; i < menu.size(); i++)
            menu.getItem(i).setVisible(false);
    }
}

In my example I've hidden all items. 在我的例子中，我隐藏了所有项目。

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#6楼

P1r4nh4 answer works fine, I just simplified it using a boolean flag: P1r4nh4答案工作正常，我只是使用布尔标志简化它：

public int mState = 0; //at the top of the code
//where you want to trigger the hide action
mState = 1; // to hide or mState = 0; to show
invalidateOptionsMenu(); // now onCreateOptionsMenu(...) is called again
...

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    // inflate menu from xml
    MenuInflater inflater = getSupportMenuInflater();
    inflater.inflate(R.menu.settings, menu);

    if (mState == 1) //1 is true, 0 is false
    {
        //hide only option 2
            menu.getItem(2).setVisible(false);
    }
}