I have two floating action buttons in a fragment that is being created by a ViewPager. My intention is for the FABs to do the same thing that can be done in the ViewPager, so that the user can have a choice in terms of navigation. My problem is that the FABs do not respond to clicks initially, so if I click the left FAB, and then click the right FAB, the ViewPager will flip to the left instead of flipping to the right. What am I doing wrong?
Here is my code:
activity_view_pager:
<?xml version="1.0" encoding="utf-8"?>
<androidx.viewpager.widget.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
fragment_test:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="50dp"
android:text="Title"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/a"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="100dp"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="200dp"
android:text="Description"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/b"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="250dp"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/c"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="300dp"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="@+id/left_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="50dp"
android:layout_marginTop="450dp"
android:src="@drawable/ic_left_arrow"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="@+id/right_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="450dp"
android:layout_marginEnd="50dp"
android:src="@drawable/ic_right_arrow"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
ViewPagerActivity:
package com.fl4me.android.exampleapplication;
import static com.fl4me.android.exampleapplication.TestAdapter.EXTRA_ID;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentStatePagerAdapter;
import androidx.viewpager.widget.ViewPager;
public class ViewPagerActivity extends AppCompatActivity {
public static int index;
public static ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_pager);
index = (int) getIntent().getSerializableExtra(EXTRA_ID);
viewPager = (ViewPager) findViewById(R.id.view_pager);
FragmentManager fragmentManager = getSupportFragmentManager();
viewPager.setAdapter(new FragmentStatePagerAdapter(fragmentManager) {
@Override
public Fragment getItem(int position) {
return TestFragment.newInstance(position);
}
@Override
public int getCount() {
return 5;
}
});
for(int i = 0; i < Test.testData.length; i++) {
if(i == index) {
viewPager.setCurrentItem(i);
break;
}
}
}
}
TestFragment:
package com.fl4me.android.exampleapplication;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.fragment.app.Fragment;
import androidx.viewpager.widget.ViewPager;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
public class TestFragment extends Fragment {
private static final String ARG_ID = "Id";
private int Id;
private String a;
private TextView aTV;
private String b;
private TextView bTV;
private int c;
private TextView cTV;
private FloatingActionButton leftBtn;
private FloatingActionButton rightBtn;
public static TestFragment newInstance(int Id) {
Bundle args = new Bundle();
args.putSerializable(ARG_ID, Id);
TestFragment fragment = new TestFragment();
fragment.setArguments(args);
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_test, container, false);
Id = getArguments().getInt(ARG_ID);
a = Test.testData[Id].getA();
b = Test.testData[Id].getB();
c = Test.testData[Id].getC();
aTV = (TextView) view.findViewById(R.id.a);
aTV.setText(a);
bTV = (TextView) view.findViewById(R.id.b);
bTV.setText(b);
cTV = (TextView) view.findViewById(R.id.c);
cTV.setText(String.valueOf(c));
leftBtn = view.findViewById(R.id.left_btn);
rightBtn = view.findViewById(R.id.right_btn);
leftBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
ViewPagerActivity.viewPager.setCurrentItem(ViewPagerActivity.index--);
}
});
rightBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
ViewPagerActivity.viewPager.setCurrentItem(ViewPagerActivity.index++);
}
});
return view;
}
}
