We can judge from the following two aspects: 1. External Screen: the main use of the external screen is touch; touch is not good, touch drift, can not touch, are caused by the external screen, can be replaced, also, if the display can't be touched, the touch is broken, which means the external screen is broken.
2. The inner screen: the main purpose of the inner screen is to display; just look at the outside and there are no signs of cracking, just not showing the image. That's the inner screen breaking down the cracks in the light shining on the phone, if there are many cracks on the outside screen, and the picture on the inside screen is not complete, then the inside and outside screen are broken. If the phone's touch fails, and the image appears striped or black, it's likely that the phone's internal and external screens are cracked.
