Android工具栏不显示溢出菜单

我是android应用程序的新手，我希望有一个目光敏锐的人能发现我做错了什么。我试着按照这些步骤为我的应用程序创建一个工具栏。但是，它没有显示三点溢出菜单（我认为是自动的）

以下是我看到的：

<resources>
    <!--
        Base application theme, dependent on API level. This theme is replaced
        by AppBaseTheme from res/values-vXX/styles.xml on newer devices.
    -->
    <style name="AppTheme.Base" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="android:windowNoTitle">true</item>
        <item name="windowActionBar">false</item>
    </style>

    <style name="AppBaseTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!--
            Theme customizations available in newer API levels can go in
            res/values-vXX/styles.xml, while customizations related to
            backward-compatibility can go here.
        -->
    </style>

    <!-- Application theme. -->
    <style name="AppTheme" parent="AppBaseTheme">
        <!-- All customizations that are NOT specific to a particular API-level can go here. -->
    </style>

</resources>

<android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@android:color/darker_gray"
            android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

我正在使用MinsdkVersion19

mainacivity.java

import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;


public class MainActivity extends AppCompatActivity {

@SuppressLint("ShowToast")
@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
    setSupportActionBar(myToolbar);

layout\main.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:descendantFocusability="beforeDescendants"
android:focusableInTouchMode="true">

<android.support.v7.widget.Toolbar
    android:id="@+id/my_toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    android:elevation="4dp"
    android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>

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

<item
    android:id="@+id/action_settings"
    android:orderInCategory="100"
    android:title="@string/action_settings"
    app:showAsAction="never"
    android:visible="true" />

<resources>
<!--
    Base application theme, dependent on API level. This theme is replaced
    by AppBaseTheme from res/values-vXX/styles.xml on newer devices.
-->
<style name="AppTheme.Base" parent="Theme.AppCompat.Light">
    <item name="android:windowNoTitle">true</item>
    <item name="windowActionBar">false</item>
</style>

<style name="AppBaseTheme" parent="Theme.AppCompat.Light">
    <!--
        Theme customizations available in newer API levels can go in
        res/values-vXX/styles.xml, while customizations related to
        backward-compatibility can go here.
    -->
</style>

<!-- Application theme. -->
<style name="AppTheme" parent="AppBaseTheme">
    <!-- All customizations that are NOT specific to a particular API-level can go here. -->
</style>

menu\main.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:descendantFocusability="beforeDescendants"
android:focusableInTouchMode="true">

<android.support.v7.widget.Toolbar
    android:id="@+id/my_toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    android:elevation="4dp"
    android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>

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

<item
    android:id="@+id/action_settings"
    android:orderInCategory="100"
    android:title="@string/action_settings"
    app:showAsAction="never"
    android:visible="true" />

<resources>
<!--
    Base application theme, dependent on API level. This theme is replaced
    by AppBaseTheme from res/values-vXX/styles.xml on newer devices.
-->
<style name="AppTheme.Base" parent="Theme.AppCompat.Light">
    <item name="android:windowNoTitle">true</item>
    <item name="windowActionBar">false</item>
</style>

<style name="AppBaseTheme" parent="Theme.AppCompat.Light">
    <!--
        Theme customizations available in newer API levels can go in
        res/values-vXX/styles.xml, while customizations related to
        backward-compatibility can go here.
    -->
</style>

<!-- Application theme. -->
<style name="AppTheme" parent="AppBaseTheme">
    <!-- All customizations that are NOT specific to a particular API-level can go here. -->
</style>

styles.xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:descendantFocusability="beforeDescendants"
android:focusableInTouchMode="true">

<android.support.v7.widget.Toolbar
    android:id="@+id/my_toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    android:elevation="4dp"
    android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>

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

<item
    android:id="@+id/action_settings"
    android:orderInCategory="100"
    android:title="@string/action_settings"
    app:showAsAction="never"
    android:visible="true" />

<resources>
<!--
    Base application theme, dependent on API level. This theme is replaced
    by AppBaseTheme from res/values-vXX/styles.xml on newer devices.
-->
<style name="AppTheme.Base" parent="Theme.AppCompat.Light">
    <item name="android:windowNoTitle">true</item>
    <item name="windowActionBar">false</item>
</style>

<style name="AppBaseTheme" parent="Theme.AppCompat.Light">
    <!--
        Theme customizations available in newer API levels can go in
        res/values-vXX/styles.xml, while customizations related to
        backward-compatibility can go here.
    -->
</style>

<!-- Application theme. -->
<style name="AppTheme" parent="AppBaseTheme">
    <!-- All customizations that are NOT specific to a particular API-level can go here. -->
</style>

真的
假的

---

我想你错过了这个

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

---

如果你的手机有一个物理菜单按钮，你看不到三个点

如果要强制显示三个点，请执行以下操作：

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

<item
    android:id="@+id/menu"
    app:showAsAction="always"
    android:icon="@drawable/ic_action_overflow"
    android:visible="true" >
 <menu>
    <item
    android:id="@+id/action_settings"
    android:orderInCategory="100"
    android:title="@string/action_settings"
    app:showAsAction="never"
    android:visible="true" />
 </menu>
</item>

---

解决方案：我尝试了以下方法，发现了问题

我认为这是将该主题引用到

theme.AppCompat.Light

这就是为什么该主题有一个工具栏

我刚做了这件事，它正在工作：

<resources>
    <!--
        Base application theme, dependent on API level. This theme is replaced
        by AppBaseTheme from res/values-vXX/styles.xml on newer devices.
    -->
    <style name="AppTheme.Base" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="android:windowNoTitle">true</item>
        <item name="windowActionBar">false</item>
    </style>

    <style name="AppBaseTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!--
            Theme customizations available in newer API levels can go in
            res/values-vXX/styles.xml, while customizations related to
            backward-compatibility can go here.
        -->
    </style>

    <!-- Application theme. -->
    <style name="AppTheme" parent="AppBaseTheme">
        <!-- All customizations that are NOT specific to a particular API-level can go here. -->
    </style>

</resources>

<android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@android:color/darker_gray"
            android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

p.s:另外，我想确保你能做到完美，正如医生所说，我们必须将此添加到

清单中

：

<application
    android:theme="@style/Theme.AppCompat.Light.NoActionBar"
    />

---

而且似乎它不起作用或者我们丢失了一些东西。顺便说一句，我没有在我的清单上这样做，而且清单上没有上面的代码就修复了这个问题。

我也有同样的问题。我尝试了这里的一切，但没有任何帮助。一切都像它应该的那样。经过一整天的调查，我在onCreate方法中发现了以下语句：

toolbar.setVisibility(View.INVISIBLE);

---

当我移除它时，geuss what happend:3 dots菜单现在出现了，就像它应该出现的一样。

在遵循所有答案的建议后，溢出按钮仍然没有显示出来。我就是这样解决的：

• 确保覆盖活动中的“OnPrepareOptions菜单”和“OnCreateOptions菜单”两种方法
• 返回总是正确的

检查Activity.java上此方法的返回注释：

---

@return要显示菜单，您必须返回true，如果返回false，则不会显示该菜单。

在

onCreate视图中调用
设置选项菜单（true）

如果您正在从一个片段中扩展菜单，例如，通过覆盖
onCreateOptions菜单
方法。
即使最晚在2016年底，培训文档中也没有此重要说明。也许需要更新？命令行开发人员在之前插入：
import android.view.Menu