Try These Apps with Zello, VoicePing, or Voxer
Companion Apps That Make Your Walkie Talkie Apps Experience Better
Displays a permanent button on your screen so that you can use PTT no matter which other app you are currently using.
PTT from anywhere. Because the buttons are fixed to a certain position, you might even be able to use it without touching the screen
Select any installed app to run automatically when you unlock your screen
When you use After Unlock to automatically open your favorite PTT app, you can instantly jump to replying via the hard button PTT that works only when your PTT app is open.
Start push to talk by pressing your volume key even when your phone is locked
QuickClick allows you to map volume key presses to certain actions. To make it work with PTT app, Select Music (Music Player Action) -> Play -> and your Walkie Talkie App.
Then go into your PTT app and select custom Button or Actions and press the same Volume button.
Once you are setup, switch the screen off and try to see if the PTT app responds to your Volume Key Press.
Do note that I have observed that QuickClick does take up some extra battery power so you can probably only start the app when you have periods of high Walkie Talkie Activity.
Prevent your bluetooth speakers/receiver from going to standby.
But Walkie Talkie users know that Walkie Talkies might be silent for a long time and a message might come in after hours of no audio.
However if your accessory switches off, you might lose the Audio coming through the Bluetooth Speaker or Headset.
To ensure that you will still get messages heard, you can install BlueTooth KeepAlive app so they are always on.