java - Why am I getting an error when making a FragmentPageAdapter? -

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im working through tutorial can slide through tabs in view. requires me make subclass of fragmentpageadapter - in case: 

public class pageradapter extends fragmentpageradapter { ... }

i have implemented of abstract methods reason getting following error: there no default constructor available in 'android.support.v4.app.fragmentpageadapter'

does know how can fix this? highly appreciated.

if don't specify constructor in class pageradapter , default constructor no-args used, looks parent class no-args constructor, equivalent to.

public pageradapter(){        super(); // looks constructor public fragmentpageradapter (){}   }

in parent class fragmentpageradapter there below constructor defined 

public fragmentpageradapter (fragmentmanager fm)

now rule in java is, once constructor arguments defined , default no-args constructor not available unless explicitly define it. here public fragmentpageradapter (){} not there. that's why super() call fails find no-args default constructor , error.

to handle this, in class pageradapter need have constructor invoke correct super class constructor 

public pageradapter(fragmentmanager fm){        super(fm);   }

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