在projiect的子目录下，找到res/values/styles.xml
只需要加入一条 true在对应位置即可！
<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="AppBaseTheme" parent="android:Theme.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">
<item name="android:windowNoTitle">true</item>
<!-- All customizations that are NOT specific to a particular API-level can go here. -->
</style>
</resources>