question: public IntentBuilder addStream ( Uri streamUri ) { Uri currentStream = mIntent . getParcelableExtra ( Intent . EXTRA_STREAM ) ; if ( currentStream == null ) { return setStream ( streamUri ) ; } if ( mStreams == null ) { mStreams = new ArrayList < Uri > ( ) ; } if ( currentStream != null ) { mIntent . removeExtra ( Intent . EXTRA_STREAM ) ; mStreams . add ( currentStream ) ; } mStreams . add ( streamUri ) ; return this ; }
target:  Add a stream URI to the data that should be shared. If this is not the first stream URI added the final intent constructed will become an ACTION_SEND_MULTIPLE intent. Not all apps will handle both ACTION_SEND and ACTION_SEND_MULTIPLE.