android-activity之singleTop启动模式_将 activity 的 launchmode 设置成了 “singletop” 模式-优快云博客

本文链接：https://blog.youkuaiyun.com/wangpanbaoding/article/details/50379923

本文通过示例展示了Activity启动模式singleTop的工作原理。当ActivityA设置为singleTop模式并处于栈顶时，再次启动将不会创建新的实例，而是复用当前实例。文章通过dumpsys命令输出了不同Activity的启动过程及栈状态。

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配置清单文件中设置ActivityA启动模式为singleTop
应用启动，打开ActivityA
ACTIVITY MANAGER ACTIVITIES (dumpsys activity activities)
Display #0 (activities from top to bottom):
Stack #27:
    Task id #180
    * TaskRecord{8c2a501 #180 A=com.wp.launchmode U=0 sz=1}
      * Hist #0: ActivityRecord{a73aae8 u0 com.wp.launchmode/.ActivityA t180}

Stack #0:

打开ActivityB
ACTIVITY MANAGER ACTIVITIES (dumpsys activity activities)
Display #0 (activities from top to bottom):
Stack #27:
    Task id #180
    * TaskRecord{8c2a501 #180 A=com.wp.launchmode U=0 sz=2}
      * Hist #1: ActivityRecord{f829c85 u0 com.wp.launchmode/.ActivityB t180}
      * Hist #0: ActivityRecord{a73aae8 u0 com.wp.launchmode/.ActivityA t180}

Stack #0:

打开ActivityC
ACTIVITY MANAGER ACTIVITIES (dumpsys activity activities)
Display #0 (activities from top to bottom):
Stack #27:
    Task id #180
    * TaskRecord{8c2a501 #180 A=com.wp.launchmode U=0 sz=3}
      * Hist #2: ActivityRecord{c7ab81d u0 com.wp.launchmode/.ActivityC t180}
      * Hist #1: ActivityRecord{f829c85 u0 com.wp.launchmode/.ActivityB t180}
      * Hist #0: ActivityRecord{a73aae8 u0 com.wp.launchmode/.ActivityA t180}

Stack #0:

打开ActivityD
ACTIVITY MANAGER ACTIVITIES (dumpsys activity activities)
Display #0 (activities from top to bottom):
Stack #27:
    Task id #180
    * TaskRecord{8c2a501 #180 A=com.wp.launchmode U=0 sz=4}
      * Hist #3: ActivityRecord{a1952a8 u0 com.wp.launchmode/.ActivityD t180}
      * Hist #2: ActivityRecord{c7ab81d u0 com.wp.launchmode/.ActivityC t180}
      * Hist #1: ActivityRecord{f829c85 u0 com.wp.launchmode/.ActivityB t180}
      * Hist #0: ActivityRecord{a73aae8 u0 com.wp.launchmode/.ActivityA t180}

Stack #0:

打开ActivityA
ACTIVITY MANAGER ACTIVITIES (dumpsys activity activities)
Display #0 (activities from top to bottom):
Stack #27:
    Task id #180
    * TaskRecord{8c2a501 #180 A=com.wp.launchmode U=0 sz=5}
      * Hist #4: ActivityRecord{b6c3b80 u0 com.wp.launchmode/.ActivityA t180}
      * Hist #3: ActivityRecord{a1952a8 u0 com.wp.launchmode/.ActivityD t180}
      * Hist #2: ActivityRecord{c7ab81d u0 com.wp.launchmode/.ActivityC t180}
      * Hist #1: ActivityRecord{f829c85 u0 com.wp.launchmode/.ActivityB t180}
      * Hist #0: ActivityRecord{a73aae8 u0 com.wp.launchmode/.ActivityA t180}

Stack #0: