* Main ---------------------------------------------------------- ***** xml <? xml version= "1.0" encoding= "utf-8" ?> < LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android" android :layout_width= "match_parent" android :layout_height= "match_parent" android :orientation= "vertical" xmlns: tools = "http://schemas.android.com/tools" > < LinearLayout android :orientation= "horizontal" android :layout_width= "match_parent" android :layout_height= "wrap_content" > < Button android :layout_width= "wrap_content" android :layout_height= "wrap_content" android :text= "fragment1" android :id= "@+id/button1" android :layout_weight= "1" android :onClick= "selectFrag" /&