How i can use findViewById() in Android?

Question

Basically the problem is that, when you want to use the method "FindViewById" or "GetSystemService" or other does not let me.

He only lets me use them in MainActivity, I wanted to know how I can solve this problem.

I'm new to android Studio and I'm basically learning

MainAtivity

public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        switch (position){
            case 0:
                tap1alarmas tap1 = new tap1alarmas();
                return tap1;
            case 1:
                tap2tips tap2 = new tap2tips();
                return tap2;
            case 2:
                tap3estadisticas tap3 = new tap3estadisticas();
                return tap3;
            default:
                return null;

        }
    }

Fragment "Tap1alarmas"

import android.app.AlarmManager;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.TimePicker;

import java.util.Calendar;


public class tap1alarmas extends Fragment {


AlarmManager alarm_manager;
TimePicker alarm_timepicker;
TextView update_text;
tap1alarmas context;


private MainActivity.SectionsPagerAdapter mSectionsPagerAdapter;

private ViewPager mViewPager;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

this.context = this;

//Inicizaliar alarmmanager
alarm_manager = (AlarmManager) getSystemService(ALARM_SERVICE);

//Inicializar timepicker

alarm_timepicker = (TimePicker) findViewById(R.id.TimePicker);

//Text uptate`enter code here`

update_text = (TextView) findViewById(R.id.update_text);

Those are functions on Context. You must call them either in a Context, or on a Context. — Gabe Sechan, Oct 03 '18 at 18:55
In very simple language: you can use **findViewById(R.id.your_id)** anywhere in your Activity, But when you're in a Fragment, you need to have a reference to your View object (which is accessible from onCreateView method) **view.findViewById(R.id.your_id);** — Joe, Oct 03 '18 at 19:01

ʍѳђઽ૯ท · Accepted Answer · 2018-10-03T19:00:19.713

If you're trying to use findViewById in Fragment, first of all make sure you're using onCreateView() and you're returning the view at the end.

See the differences in here: Difference and uses of onCreate(), onCreateView() and onActivityCreated() in fragments

Here is an example for that:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_single_image, parent, false);

    alarm_timepicker = (TimePicker) rootView.findViewById(R.id.TimePicker); 
    // your widgets with rootView prefix

    return rootView;
}

rootView is the point here. So, if you want to declare any widgets (or etc), use rootView in this case as a prefix before referecning your id by findViewById.

An addendum, for `getSystemService()`, you can call `getActivity().getSystemService()` — TEK292, Oct 03 '18 at 18:58

How i can use findViewById() in Android?

MainAtivity

Fragment "Tap1alarmas"

1 Answers1