Pass data between 2 child fragments nested in 1 fragment android -

i've been working on nested fragments in android. have activity contains fragment , fragment contains fragment a1 , fragment a2. , far, can pass data fragment a1 parent fragment(fragment a) using getparentfragment() (also fragment a2). how can pass data fragment a1 fragment a2? approach must used , how?

approach 1: data fragment a1 --> pass data parent fragment (fragment a) --> pass data fragment a2 (usual approach in passing data between fragments)

or

approach 2: fragment a1 --> pass data directly fragment a2 via settargetfragment()/gettargetfragment()

i've been experimenting set/gettargetfragment() quite time still can't make work. need guys. thanks!

approach1 good.. communication between 2 fragments should occur via parentfragment (or parentactivity), "sync" , "single point o access" sustain.