Here’s how to unlock the screen on Android phones using the volume up button.
This is a very useful method for phones that do not work properly because the power button on the phone is often turned on and off. This is done using a third party app, but you can use it even if your phone is not rooted. However, the Android version of the phone must be v4.1 and above.
First, tap the PlayStore to install the required app on your phone.
Then type volume unlock in the search box. You should see something like this: Select the text with the icon as shown in the image.
This will prompt you to install the app and click the INSTALL button.
Please wait for the installation. Then find the App icon on your phone and open it again.
You should see something like this: Click on the box next to Enable / Disable Screen wake. This will change the text from DISABLED below it to ENABLED. Then click the button next to Use volume key to lock.
Click the button next to Use volume key to lock to activate, and then click Activate in the lower left corner of the screen.
When you click Activate, you will see a message like this: You can now turn on and off the phone screen by pressing the volume up button. The phone screen unlock can be unlocked by pressing the volume button once and locking it twice.