Android工具栏没有显示溢出菜单

Question

我是Android应用的新手,我希望有敏锐眼光的人能发现我做错了什么.我试图按照这里的步骤,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).

这是我看到的:

我正在使用minSdkVersion 19.

MainAcivitiy.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);

布局\ main.xml中

<?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"/>

菜单\ main.xml中

<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" />

styles.xml

<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>

Answer 1

我猜你错过了这个

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