There are several libraries available that will assist you in implementing tooltips in Android.
I recommend the Android Tooltip library which you can find on Github
Example usage:
Tooltip.make(this,
new Builder(101)
.anchor(aView, Gravity.BOTTOM)
.closePolicy(new ClosePolicy()
.insidePolicy(true, false)
.outsidePolicy(true, false), 3000)
.activateDelay(800)
.showDelay(300)
.text(R.string.hello_world)
.maxWidth(500)
.withArrow(true)
.withOverlay(true)
floatingAnimation(AnimationBuilder.DEFAULT)
.build()
).show();