app啟動流程:冷啟動,熱啟動,暖啟動

前言:項目中被诟病多媒體開機第一次啟動很慢,大約3s的黑屏,後續點開啟動正常,其中什麼原理呢?這就涉及到系統的三種啟動模型

1.Cold Start,冷啟動

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,熱啟動

前台activity因記憶體不足,被系統銷毀重建的過程(重建流程同冷啟動)

3.Warm Start

• 使用者點選傳回,并重新運作

• activity不在前台,被系統銷毀,由使用者主動運作

  可通過onSaveInstance儲存狀态

4.APP啟動慢常見問題

• Application.onCreate中執行了過重的操作,如I/O操作,頻繁建立對象等

• Activity.onCreate

  布局過于複雜

  Loading and decoding bitmaps

  blocking screen drawing on disk or network I/O

  Rasterinzing vectordrawable objects

  initialztion of other subsystem of the activity