You may be unfamiliar with Callkit. It is most familiar with the lock screen interface. Wechat and other application calls can directly display the 'reject' and 'answer' full-screen interface. This experience is almost no different from the traditional call experience.
However, according to the regulations of the relevant authorities, this feature must be screened in China, and this has the greatest impact on applications such as Wechat. Because there are voices, when the video phone is entered, you will not see the direct and clear Answer or hang up the interface prompt, replace it with a new message, want to see the need to enter the App.
In addition to iOS, Android phones actually provide this function. When the screen is locked, the network call interface pops up directly. This may be inconvenient for the user, but considering the traditional call service, it is easy to understand.