一、查找应用的主activity：

  pm list packages 发现所有的包

  dumpsys package + 包名： 获取所有的包信息，可以所有关键词MAIN来找主activity

  也可以通过下面命令找到所有activity，看下面大概率com.android.settings/.Settings为主activity

  dumpsys package com.android.settings | grep -i activity

2dee926 com.android.settings/.Settings$AdvancedConnectedDeviceActivity filter d570967 9a0114d com.android.settings/.Settings$AutomaticStorageManagerSettingsActivity filter cfb0402

37c7254 com.android.settings/.Settings$AppBubbleNotificationSettingsActivity filter 7ca75fd 47c7621 com.android.settings/.Settings$ApnEditorActivity filter 3828a46

47c7621 com.android.settings/.Settings$ApnEditorActivity filter 3828a46 c5ef02b com.android.settings/.Settings$PublicVolumeSettingsActivity filter ddb8c88

47c7621 com.android.settings/.Settings$ApnEditorActivity filter cda6407

二、例子8295:

 #:/ # pm list packages | grep -i setting                                                                                                                                                                     
package:com.android.providers.settings
package:com.android.settings

# dumpsys package  com.android.settings | grep -i activity                                               Activity Resolver Table:
        6124ef5 com.android.settings/.Settings$ApnEditorActivity filter 58748a
        5071fdf com.android.settings/.Settings$PublicVolumeSettingsActivity filter 538b42c
        6124ef5 com.android.settings/.Settings$ApnEditorActivity filter 5e7dafb
 

最后：

am start -n "com.android.settings/.Settings"

三、CloudCampus iperf华为测试工具，查找包名以及其主activity

  dumpsys package com.huawei.acceptance | grep -i activity

  am start -n com.huawei.acceptance/.PrivatePolicyMainActivity

am start -n com.nextdoordeveloper.miperf.miperf/.MainActivity

四、Wifi  P2P的包和启动命令：

am start -n "github.leavesczy.wifip2p/.MainActivity"

am start -n "com.example.testsystem/.MainActivity"