jkhosla

If one finds the dev tools all gone post a macOS Update.
Open the terminal and 
  xcode-select -- install 

jkhosla

//for minSDKVersion 16 
// in the layout xml on the editText

android:maxLength="5"

jkhosla

// This is kind of tricky. 
// To do this programitacally and for minSDKVersion 16 

// Import statement -
import android.support.v7.app.ActionBar;

//Usage
void onCreate {
    ActionBar actionBar = getSupportActionBar();
    actionBar.hide();