android/view/view$on unhandled keyevent listener error

问题

When i create a new layout in Android Studio , I can't put anything on it literally (with root element android.support.v7.widget.Toolbar, by going layout->new->ressourse file)

I can't even change the background color! it shows me

"android/view/view$on unhandled keyevent listener"

the error is on the photo number 2

回答1:

I don't see anything underlined. Try the following

---

1. Install the missing plattforms like Android Studio suggests in your screenshot from the comments

2. Be sure to add implementation 'com.android.support:appcompat-v7:27.1.1' to your build.gradle

3. If that doesn't work maybe it's just a rendering problem for the design preview. Therefore you can switch to another Theme right above the UI which says AppTheme.

Let me know if this helps

回答2:

//noinspection GradleCompatible
implementation 'com.android.support:appcompat-v7:27.1.1'
//noinspection GradleCompatible
implementation 'com.android.support:design:27.1.1'

add these two library hope this will work

来源：https://stackoverflow.com/questions/51433013/android-view-viewon-unhandled-keyevent-listener-error