How to set global variable in Kotlin
1. put this on top:
```
object GlobalVariable {
var mp = MediaPlayer()
}
```
2. use it everywhere
`GlobalVariable.mp`
3. so you won't have to worry about open too many MediaPlayer at the same time
```
object GlobalVariable {
var mp = MediaPlayer()
}
```
2. use it everywhere
`GlobalVariable.mp`
3. so you won't have to worry about open too many MediaPlayer at the same time