Action bar does not show

Question

I tried to implement an action bar in my application.

menu.xml

Answer 1

I import import android.support.v7.app.AppCompatActivity;

then edit to public class MainActivity extends AppCompatActivity

Add to dependencies

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:25.0.0'
}