The following classes could not be instantiated: - android.support.design.widget.FloatingActionButton

问题

I receive the following error

The following classes could not be instantiated: - android.support.design.widget.FloatingActionButton

Lately that problem appears every time I opened new project in Android Studio, I tried many solutions written here, like ..

• Rebuild and re-sync project with gradle option.
• Change Android rendering version.
• Checking updates and install latest version.

None of those solutions work for me.

回答1:

Try update "build.gradle (Module.app)" like this:

...
dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.2.1'
    compile 'com.android.support:support-annotations:23.2.1'
    compile 'com.android.support:design:23.2.1'
}
...

and resync project. It helped me

回答2:

I found a solution which is changing project theme in res/values/styles.xml

<stylename="AppTheme"parent="Theme.AppCompat.Light.DarkActionBar">

and it worked.

来源：https://stackoverflow.com/questions/35924773/the-following-classes-could-not-be-instantiated-android-support-design-widget