When the UID of the application is system, it cannot be installed directly on the Android machine, and it will prompt "installation failed" or "the application is not installed";
As shown in the picture:
problem causes:
Because the system signature is inconsistent, you need to get the system signature, and then re-sign the application.
problem solved:
(1) Prepare the signature tool signapk.jar (tool link: signature tool signapk.jar-Android Documentation Resources-CSDN Download )
(2) Get the signature files .pem and .pk8 required by the machine system application (such as platform.pk8 and platform.x509.pem)
(3) Put the application to be signed (such as text.apk), signapk.jar, .pem and .pk8 signature files into the same directory file (such as C:\Users\Desktop\key directory)
(4) Then open the cmd command window, cd into the directory in (3)
(5) Use the following command:
C:\Users\Desktop\key> java -jar signapk.jar platform.x509.pem platform.pk8 text.apk 123.apk
Explanation: signapk.jar is the signature file, platform.x509.pem platform.pk8 is the signature file, text.apk is the application that needs to be signed, and 123.apk is the re-signed application.
(6) The re-signed application 123.apk can now be installed directly in the file manager