How to extract apk from miui status bar

Hello, first of all, I tried to extract the original MiuiSystemUI.apk file from the latest MIUI4.4.25 credit card package I upgraded, and then put it into my mobile phone with re file management. I modified the read and write permissions three times, but it still didn't work after restarting. If this method fails, I can use the method I describe below. This method is best used on the premise that it cannot be solved after repainting the machine.

After swiping the card, the latest system restarts, so it won't work. Then we back up the mobile phone files and turn it off, and then press and hold the volume up button and the power off button to enter the recovery mode. Select Simplified Chinese-Clear Data, then select the first one to clear the cache, then select the second one to clear the user data, and then ensure that the clearing is completed. Remember that the third one will clear everything. Don't worry about the data, it doesn't affect us. After clearing these two things, the chance of restarting the mobile phone is very slow, because this method is equivalent to clearing all the settings of your mobile phone, but the file software and the like will not be cleared. After the boot is completed, it is the setting interface when you first open Xiaomi, set the language, Xiaomi account, etc., and then select the data you backed up before in your backup. Then directly start the backup, which can completely solve the problems such as the disappearance of status bar and black screen caused by the modification of MiuiSystemUI.apk sent by me after Xiaomi 2S pro-test.