Ionic 4: android emulator whitescreen

prob%201
prob%202

Hi, im using ionic 4. first i want to test my app in android emulator…so i open android studio and open avd… then im using command cmd navigate my ionic project and run ‘ionic cordova run android’ my emulator open normally but when turns to open my app,its just whitescreen… then i try to inspect chrome to see what error in console… but its just show nothing… can somebody help me… im very clueless