qt android arm64-v8a not launching the simplest ui but works fine in armeabi-v7a

[leoluopy]

i am using qt 5.12 android , it works fine at armeabi-v7a .
and to begin with , it can not compile the arm64-v8a after i set ANDROID_NDK_PLATFORM=android-21 , then arm64-v8a can be properly compiled . but when i launch it , it shows not ui items, but a full white screen. any one can help ?
addition informations:
1 . i design the ui using qt designer , i only has a simplest label and a pushbutton
2. all code and configs are uploaded at baidu cloud
链接: https://pan.baidu.com/s/1ooUXdnpl_nL8uK8lFxIZyQ 提取码: ksw2 复制这段内容后打开百度网盘手机App，操作更方便哦
3. contact me by email : 8944105@qq.com or wechat ID: leoluopy
4. the app launches properly in both x86 emulator and a ameabi-v7a real machine debugging

[leoluopy]

I have fixed it after a period of debugging . but it's not likely going to appear every time . Or if you install your environment the first time , the phenomenon will not appear .
i fix it just add by the fellowing approach :
QT += core gui multimedia multimediawidgets