[Solved] You need to use a Theme.AppCompat theme (or descendant) with this activity.

@[TOC](You need to use a Theme.AppCompat theme (or descendant) with this activity. in Android error message.)

1. The following error is reported

The reason is: Activty inherits from android.support.v7.app.AppCompatActivty, not android.app.Activty.

2. Solutions

Look at the prompt, that is, use AppCompat in Theme to change the theme used in AndroidManifist.xml.

<activity android:name=".activity.GywmActivity"
            android:label="About us"
            android:theme="@style/Theme.AppCompat.Dialog">
        </activity>

Perfect solution!