This app was mentioned in 25 comments, with an average of 2.24 upvotes
There's tons of awesome apps on the play store.
They just get buried underneath all the fake malware crap.
Like take Cool Tool. Awesome piece of software, lets you display pretty much whatever system stats you want in your notification bar, at all times. But if you just went searching for its keywords like "system monitoring tool", it'd be buried under literally a hundred shitty fake chinese malware crap.
The only reason I even know of apps like these is because I spent hours searching the play store, back when it was called google Marketplace, for cool or interesting apps, and the store hadn't been flooded with crap yet. They're still there, you're just never, ever going to find them using the Play store's own search engine.
The only way to find out about cool apps nowadays is either someone mentioning it, or reading "top apps" articles.
It's an app called Cool Tool. Been using it for years to keep a good eye on phone management. Not sure if it's available on iOS though. I have it set to show battery, CPU usage, CPU clock speed, available RAM, temperature and internet download/upload speed (including wifi).
The widget is moveable so you can literally drag it and leave it anywhere
Cool Tool is exactly the app you're looking for. Not only can it display the free RAM on top of any app, but also the CPU, Battery, WiFi, CPU temperatures etc. All fully customisable of course. ��
Cool Tool:
https://play.google.com/store/apps/details?id=ds.cpuoverlay&hl=en
And yes it is super sweet. Totally customizable, you can even point it to custom... linux... things... where unique stats are stored. For example I found a live milliamp meter in /sys/class/power_supply/battery to get 100% accurate and updated every second current usage.
Cool Tool:
https://play.google.com/store/apps/details?id=ds.cpuoverlay&hl=en
Normally it's just an overlay that will actually display on top of the notification bar, which means it will overlap things if you have too much stuff on your bar. But if you are rooted and have xposed, you can actually make it part of the notification bar, where it will automatically move around to make room for other notifications.
I use an app called Cool Tool to monitor my RAM usage. Currently, Lollipop has a memory leak issue that hopefully should be fixed in the newest update of 5.1.1, which has begun reaching nexus devices, so depending on your carrier, should hopefully get it soon.
As for a fix, usually when it starts happening, if you restart your phone, it should get rid of the issue for a while, but this is an android wide issue at the moment that google worked (and could still be working) hard to fix and it should be fixed soon.
Cool Tool for Android:
https://play.google.com/store/apps/details?id=ds.cpuoverlay&hl=en
You can customize it to display any information you want, like cpu usage, memory, temperature, bandwidth speed, in any from, from text numerical, to a histogram graph like you see of my cpu usage behind the text, to a vertical bar like you see on the far left for my cpu clock speed. You can set it up to be always visible or to automatically hide in fullscreen apps when the notification bar is hidden. You can change the font size, the number of lines of text, the width of the graph, the colours, everything.
It's completely free, but there is a pro version that unlocks logging and a special xposed module. The free version is completely functional and does everything you could ever need.
You can get an app called Cool Tool to put various text as an overlay anywhere on the screen.
https://play.google.com/store/apps/details?id=ds.cpuoverlay
I put my battery percentage centered in my notification bar. I also put my cpu frequency there so I know of my phone is actually doing something vs locking up.
Additionally to the Xposed module you can use CoolTool. It has what you want and more. I've been using it for a very long time now and have no complaints.
https://play.google.com/store/apps/details?id=ds.cpuoverlay
I've configured mine to show both the battery and cpu temp.
Cool tools is what your looking for
Cool tool - system stats can display current bandwidth as an overlay.
see if this helps
https://play.google.com/store/apps/details?id=ds.cpuoverlay&hl=en
Not exactly what you asked for but this may be useful
Cool Tools can have a battery overlay and a battery temp feature.
You could try cool tool
"Cool Tool." It's heavily customizable, and is available free on the Play Store.
https://play.google.com/store/apps/details?id=ds.cpuoverlay&hl=en