优化

app/src/main/java/io/legado/app/base/BaseActivity.kt

@@ -10,6 +10,7 @@ import android.view.Menu
 import android.view.MenuItem
 import android.view.View
 import android.widget.FrameLayout
+import androidx.annotation.RequiresApi
 import androidx.appcompat.app.AppCompatActivity
 import androidx.viewbinding.ViewBinding
 import io.legado.app.R
@@ -78,6 +79,7 @@ abstract class BaseActivity<VB : ViewBinding>(
         observeLiveBus()
     }
 
+    @RequiresApi(Build.VERSION_CODES.O)
     override fun onMultiWindowModeChanged(isInMultiWindowMode: Boolean, newConfig: Configuration) {
         super.onMultiWindowModeChanged(isInMultiWindowMode, newConfig)
         findViewById<TitleBar>(R.id.title_bar)