Opening activity from fragment force close error

Question

So today I created tab view bar and fragments and added some image buttons to one of the fragments. When I add android:onClick="name"on the button code and write Intent in .java file, it gives me force close error when I click on that button.

Here's my code:

fragment.xml

<ImageButton
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/btnProgramiPL5x5"
            android:minHeight="80dp"
            android:background="@mipmap/btn_programi_pl_5x5"
            android:onClick="ProgramiPowerlifting5x5"/>

fragment.java

   package hr.app.liftme.liftmehr;


import android.content.Intent;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;


/**
 * A simple {@link Fragment} subclass.
 */
public class FragmentPowerlifting extends Fragment {



    public FragmentPowerlifting() {
        // Required empty public constructor
    }




    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_powerlifting, container, false);


    }

ProgramiPowerlifting5x5.java

    package hr.app.liftme.liftmehr;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;

public class ProgramiPowerlifting5x5 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_programi_powerlifting5x5);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        Intent intent = getIntent();
    }

}

Error i get is this:

01-26 23:00:44.766 14491-14491/hr.app.liftme.liftmehr E/AndroidRuntime: FATAL EXCEPTION: main
                                                                        Process: hr.app.liftme.liftmehr, PID: 14491
                                                                        java.lang.IllegalStateException: Could not find method ProgramiPowerlifting5x5(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatImageButton with id 'btnProgramiPL5x5'
                                                                            at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:307)
                                                                            at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:266)
                                                                            at android.view.View.performClick(View.java:4856)
                                                                            at android.view.View$PerformClick.run(View.java:19956)
                                                                            at android.os.Handler.handleCallback(Handler.java:739)
                                                                            at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                            at android.os.Looper.loop(Looper.java:211)
                                                                            at android.app.ActivityThread.main(ActivityThread.java:5389)
                                                                            at java.lang.reflect.Method.invoke(Native Method)
                                                                            at java.lang.reflect.Method.invoke(Method.java:372)
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)

I don't know what is the problem, when I link two activities I use this, name.class, but that didn't worked in this case so i used getActivity and it still does not work.

I would really appreciate help!

Thanks!

Answer 1

The problem here is:

Could not find method ProgramiPowerlifting5x5(View) in a parent or ancestor Context

The onClick attribute refers to the parent Context (as parent Activity) so the fragment's method is not triggered and not handled by this attribute.
You have to handle the click in the Activity:

public class ProgramiPowerlifting5x5 extends AppCompatActivity {
    ...
    // change the method's name to avoid confusion with constuctor
    public void ProgramiPowerLifting(View view){
        Intent intent = new Intent(this, ProgramiPowerlifting5x5.class);
        startActivity(intent);
    }
}

Or trigger the same method into your fragment:

public class ProgramiPowerlifting5x5 extends AppCompatActivity {
    private ProgramPowerFragment fragment;
    ...
    public void ProgramiPowerLifting(View view){
        fragment.ProgramiPowerLifting(view);
    }
}

This great answer uses a callback interface which, personally, I'd suggest. Or you can easily forget the onClick xml attribute and do it dynamically with setOnClickListener().
So, let's try the easy way:

public class FragmentPowerlifting extends Fragment {

    public FragmentPowerlifting() { }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
        // store the layout in a view variable
        View v = inflater.inflate(R.layout.fragment_powerlifting, container, false);
        // use this view ("v") to retrieve elements on the layout by its id
        ImageButton imgButton = (ImageButton) v.findViewById(R.id.btnProgramiPL5x5);
        // set a listener to the button
        imgButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // open a new activity when onClick is triggered
                Intent intent = new Intent(getActivity(), ProgramiPowerLiftingActivity.class);
                startActivity(intent);
            }
        }
        // return the inflated view to display it
        return v;
   }
}