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

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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

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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

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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