Android ActionBar/Toolbar 在我的应用程序中消失了

Question

所以我有一个应用程序。它目前有 3 个 Activity ......我正在使用 Intent 从一个和另一个启动 Activity

MainActivity > ChallongeLogin > ChallongeEvents

在我的 MainActivity 和我的 ChallongeLogin 中，应用程序顶部有一个大栏，其中列出了我的应用程序的名称。然而，当我最终阅读 ChallongeEvents 时，这个栏消失了......我不记得做了什么特别的事情来让这个栏消失。为什么它消失了？

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.testing.testingapp">

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity
            android:screenOrientation="portrait"
            android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:screenOrientation="portrait"
            android:name=".ChallongeLogin" />

        <activity
            android:screenOrientation="portrait"
            android:name=".ChallongeEvents" />

    </application>

</manifest>

Answer 1

根据您的要求，您必须扩展 AppCompatActivity 而不是 Activity 。

public class ActivityName extends AppCompatActivity {
  // ...
}

AppCompatActivity is from the appcompat-v7 library. Principally, this offers a backport of the action bar. Since the native action bar was added in API Level 11, you do not need AppCompatActivity for that. However, current versions of appcompat-v7 also add a limited backport of the Material Design aesthetic, in terms of the action bar and various widgets. There are pros and cons of using appcompat-v7, well beyond the scope of this specific Stack Overflow answer.

引用

Activity, AppCompatActivity, FragmentActivity, and ActionBarActivity: When to Use Which?