Which mechanism is used to report android virtual buttons ?, Android buttons

Which mechanism is used to report android virtual buttons ?, Android buttons
1. In normal mode, the tp button is reported in the coordinate form of input_event like other touch events. During initialization, the coordinates of the virtual keys are written in/sys/board_properties/virtualkeys. mtk-tpd according to the configuration information defined in the tpd_custom_XXX.h file by using the tpd_button_setting () function. During work, the tp driver will report the coordinates of the pressed points. The Android upper layer will read the key configuration information in sys, and then judge whether the reported coordinates belong to the coordinate range of a certain key, in this way, the coordinate information is converted into a specific key value.
 
2. In factory mode and recovery mode, because Android has not yet started, the reporting mechanism in step 1 cannot be adopted for key events. Instead, the tpd_button () function is used to directly report keys.
 
Therefore, for normal mode, you do not need to call the tpd_button () function to report key events. In factory mode and recovery mode, you must call the tpd_button () function to report the virtual key events.
What are the mobile phones in the android system that use virtual buttons to occupy the screen? Details

Haha, Android fragmentation has been serious since 1.6 ....

How many virtual buttons can be hidden in Android 40?

Generally, Android 4.0 and later systems have three virtual buttons: The Return key, the home screen key, and the recently used key. The usage of these three keys is quite high, basically, the mobile phone cannot be used normally, so I advise the landlord not to hide these keys.