The higher version of android cannot be started normally, and occasionally an application not responding (ANR) will be reported

Recently, using a new mobile phone to test, there are frequent ANRs, and each loading is very slow. Every time the loading is slow, the following code will appear:

 After understanding, Android 9 introduces restrictions on the use of non-SDK interfaces, whether they are used directly or indirectly through reflection or JNI. This means that when manipulating a class through semantics such as reflection, you should not access functions or fields that are not listed in the SDK (there are usually @hideflags).

The meanings of blacklist, greylist, greylist-max-o, and greylist-max-p are as follows:

• blacklist Blacklist: Prohibited non-SDK interfaces, crash directly at runtime (so must be resolved)
• greylist greylist: the non-SDK interface that can still be used in the current version, but may become a restricted non-SDK interface in the next version
• greylist-max-o: A non-SDK interface that can be used in targetSDK<=O, but is prohibited in targetSDK>=P
• greylist-max-p: non-SDK interfaces that can be used in targetSDK<=P, but are prohibited in targetSDK>=Q

1. Non-SDK interface

Official document: Restrictions for non-SDK interfaces

Officially, starting from Android 9 (API level 28), restrictions have been imposed on the non-SDK interfaces used by apps.
These restrictions come into play if your app passes references 非 SDK 接口or tries 使用反射或 JNI 来获取句柄. The official explanation is for 提升用户体验、降低应用崩溃risk.

1.1. Non-SDK interface detection tool

The official has given a detection tool, download address
Google official veridex download:
https://android.googlesource.com/platform/prebuilts/runtime/+/master/appcompat

Android veridex non-SDK interface detection tool

How to use veridex:

./appcompat.sh --dex-file=文件名.apk --imprecise

The file name is veridex.gz, just decompress it directly. After decompression

Because my development environment is mac. So zip the veridex-mac.zip file, and copy the apk into it. 

 Open the terminal, cd to the current directory, and execute it.

appcompat.sh --dex-file=apk.apk

./appcompat.sh --dex-file=文件名.apk --imprecise

Supplement, both commands work. It's just --impreciseparameters, you can see more detailed information.

Copy the command line information, and check the code that needs to be modified according to the registration.

Finished - call it a day - sprinkle flowers...