Error:Execution failed for task ':app:processDebugManifest'. > Manifest merger failed with multiple

Error:Execution failed for task ':app:processDebugManifest'. > Manifest merger failed with multiple errors, see logs

<manifest xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    package="com.example.test">

<activity    android:name=".TestActivity"    android:theme="@style/IFTheme"      tools:replace="theme" />

注：没有theme的不能加