Android Toolbar菜单设置showAsAction=always仍无法正常工作求助

Hey there, let's work through this frustrating Toolbar menu issue! When your menu items aren't showing even with showAsAction="always", it usually boils down to a few common compatibility or configuration missteps. Here are the most likely fixes to try:

1. Fix the Menu XML's showAsAction Namespace #

This is the #1 culprit for AppCompat Toolbar issues. You need to use the app: namespace instead of android: for showAsAction, since the AppCompat library uses its own attribute for this.

First, make sure your menu XML has the app namespace declared at the root:

<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto">

Then update your menu item to use app:showAsAction:

<item
    android:id="@+id/your_menu_item_id"
    android:title="Your Menu Item"
    android:icon="@drawable/ic_menu_icon"
    app:showAsAction="always" />

2. Ensure Toolbar & Activity Compatibility #

• Use AppCompatToolbar: In your layout XML, confirm you're using androidx.appcompat.widget.Toolbar (not the native android.widget.Toolbar). This is required for AppCompat features.
• Extend AppCompatActivity: Your activity must inherit from AppCompatActivity (not the old Activity class) to access supportActionBar and AppCompat menu functionality.
• Use a NoActionBar Theme: Your app's theme should disable the default system ActionBar, since you're using a custom Toolbar. For example, in styles.xml:

  <style name="AppTheme" parent="Theme.MaterialComponents.Light.NoActionBar">
      <!-- Your theme attributes -->
  </style>
  

3. Correct the ActionBar Reference in initActionBar #

Instead of using the native actionBar property, use supportActionBar (from AppCompat) to avoid null references or compatibility issues:

fun initActionBar() {
    setSupportActionBar(toolbar_main)
    supportActionBar?.setDisplayHomeAsUpEnabled(true)
}

4. Verify onCreateOptionsMenu Implementation #

Your current code works, but you can simplify it slightly (it's more about readability than functionality):

override fun onCreateOptionsMenu(menu: Menu?): Boolean {
    menuInflater.inflate(R.menu.toolbar_menu, menu)
    return true
}

Just make sure you're not modifying the menu object elsewhere (like clearing it) before this method finishes.

5. Check Toolbar Layout Properties #

Ensure your Toolbar has the correct dimensions in the layout—if it's too small or hidden, menu items won't show:

<androidx.appcompat.widget.Toolbar
    android:id="@+id/toolbar_main"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    app:title="Your Toolbar Title" />

If none of these fixes work, sharing the full content of your toolbar_menu.xml and the screenshot you mentioned would help pinpoint the exact issue!

内容的提问来源于stack exchange，提问作者임세준