Solution is very simple. Find *.module.ts
files and comment declarations. In your case find addevent.module.ts
file and remove/comment one line below:
@NgModule({
declarations: [
// AddEvent, <-- Comment or Remove This Line
],
imports: [
IonicPageModule.forChild(AddEvent),
],
})
This solution worked in ionic 3 for pages that generated by ionic-cli and works in both ionic serve
and ionic cordova build android --prod --release
commands!
Be happy...