android下获取系统导航栏高度

const main = plus.android.runtimeMainActivity()  
const windowMe = main.getWindow()  
plus.android.importClass(windowMe)  
const decorView = windowMe.getDecorView()  
plus.android.importClass(decorView)  

const windowInsets = decorView.getRootWindowInsets()  
const WindowInsets = plus.android.importClass(windowInsets)  
const insets = windowInsets.getInsets(WindowInsets.Type.navigationBars())  
const navigationBarHeight = plus.android.getAttribute(insets, 'bottom')  
console.log(navigationBarHeight) // 取到的是物理像素值，需要除以dpr转为逻辑像素值