获取当前设备屏幕密度。

let screenDensity = getContext().resourceManager.getDeviceCapabilitySync().screenDensity
if (screenDensity===120) {
  //SCREEN_SDPI = 120,小规模的屏幕密度
}else if (screenDensity===160){
  // SCREEN_MDPI = 160,中规模的屏幕密度
}else  if (screenDensity===240){
  // SCREEN_LDPI = 240,大规模的屏幕密度
}else  if (screenDensity===320){
  // SCREEN_XLDPI = 320,特大规模的屏幕密度
}else  if (screenDensity===480){
  // SCREEN_XXLDPI = 480,超大规模的屏幕密度
}else  if (screenDensity===640){
  //SCREEN_XXXLDPI = 640超特大规模的屏幕密度
}