app启动流程:冷启动,热启动,暖启动

前言:项目中被诟病多媒体开机第一次启动很慢,大约3s的黑屏,后续点开启动正常,其中什么原理呢?这就涉及到系统的三种启动模型

1.Cold Start,冷启动

system--->
loding and launching the app
displaying a blank window
createing the app process

process--->
creating the application
launching the main thread
creating the main activity
inflating views
laying out the screen
perfoming the initial draw
main activity place blank window

2.Hot Start,热启动

前台activity因内存不足,被系统销毁重建的过程(重建流程同冷启动)

3.Warm Start

• 用户点击返回,并重新运行
• activity不在前台,被系统销毁,由用户主动运行
  可通过onSaveInstance保存状态

4.APP启动慢常见问题

• Application.onCreate中执行了过重的操作,如I/O操作,频繁创建对象等
• Activity.onCreate
  布局过于复杂
  Loading and decoding bitmaps
  blocking screen drawing on disk or network I/O
  Rasterinzing vectordrawable objects
  initialztion of other subsystem of the activity