fragments basics 2

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout android:layout_width="match_parent"

    android:layout_height="match_parent"

    xmlns:android="http://schemas.android.com/apk/res/android">

    <FrameLayout

        android:id="@+id/fl_container"

        android:layout_width="match_parent"

        android:layout_height="200dp">

    </FrameLayout>

    <LinearLayout

        android:layout_below="@+id/fl_container"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:orientation="horizontal"

        android:layout_alignParentBottom="true"

        android:weightSum="3">

        <Button

            android:id="@+id/bt_first_button"

            android:layout_width="0dp"

            android:layout_weight="1"

            android:layout_height="wrap_content"

            android:text="Red"/>

        <Button

            android:id="@+id/bt_second_button"

            android:layout_width="0dp"

            android:layout_weight="1"

            android:layout_height="wrap_content"

            android:text="Green"/>

        <Button

            android:id="@+id/bt_third_button"

            android:layout_width="0dp"

            android:layout_weight="1"

            android:layout_height="wrap_content"

            android:text="Blue"/>

    </LinearLayout>

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:id="@+id/fl_blue_fragment"

    tools:context=".views.fragments.RedFragment">

</FrameLayout>

<?xml version="1.0" encoding="utf-8"?>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:id="@+id/fl_green_fragment"

    tools:context=".views.fragments.RedFragment">

</FrameLayout>

<?xml version="1.0" encoding="utf-8"?>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:id="@+id/fl_red_fragment"

    tools:context=".views.fragments.RedFragment">

</FrameLayout>

public class BlueFragment extends Fragment {

    private FrameLayout mFLRootLayout;

    public BlueFragment() {

        // Required empty public constructor

    }

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container,

                             Bundle savedInstanceState) {

        // Inflate the layout for this fragment

        View redFragmentView = inflater.inflate(R.layout.fragment_blue_layout, container, false);

        mFLRootLayout = redFragmentView.findViewById(R.id.fl_blue_fragment);

        mFLRootLayout.setBackgroundColor(getResources().getColor(R.color.blue));

        return redFragmentView;

    }

}

public class GreenFragment extends Fragment {

    private FrameLayout mFLRootLayout;

    public GreenFragment() {

        // Required empty public constructor

    }

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container,

                             Bundle savedInstanceState) {

        // Inflate the layout for this fragment

        View redFragmentView = inflater.inflate(R.layout.fragment_green_layout, container, false);

        mFLRootLayout = redFragmentView.findViewById(R.id.fl_green_fragment);

        mFLRootLayout.setBackgroundColor(getResources().getColor(R.color.green));

        return redFragmentView;

    }

}

public class RedFragment extends Fragment {

    private FrameLayout mFLRootLayout;

    public RedFragment() {

        // Required empty public constructor

    }

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container,

                             Bundle savedInstanceState) {

        // Inflate the layout for this fragment

        View redFragmentView = inflater.inflate(R.layout.fragment_red_layout, container, false);

        mFLRootLayout = redFragmentView.findViewById(R.id.fl_red_fragment);

        mFLRootLayout.setBackgroundColor(getResources().getColor(R.color.red));

        return redFragmentView;

    }

}

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    @BindView(R.id.bt_first_button) Button mBTFirstButton;

    @BindView(R.id.bt_second_button) Button mBTSecondButton;

    @BindView(R.id.bt_third_button) Button mBTThirdButton;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        ButterKnife.bind(this);

        mBTFirstButton.setOnClickListener(this);

        mBTSecondButton.setOnClickListener(this);

        mBTThirdButton.setOnClickListener(this);

    }

    @Override

    public void onClick(View v) {

        switch (v.getId()) {

            case R.id.bt_first_button:

                firstButtonClicked();

                break;

            case R.id.bt_second_button:

                secondButtonClicked();

                break;

            case R.id.bt_third_button:

                thirdButtonClicked();

                break;

        }

    }

    private void firstButtonClicked() {

        FragmentUtility.showFragmentInContainer(this, new RedFragment(), R.id.fl_container);

    }

    private void secondButtonClicked() {

        FragmentUtility.showFragmentInContainer(this, new GreenFragment(), R.id.fl_container);

    }

    private void thirdButtonClicked() {

        FragmentUtility.showFragmentInContainer(this, new BlueFragment(), R.id.fl_container);

    }

}

dependencies {

//----------

//--------

    // butter knife

    implementation 'com.jakewharton:butterknife:8.8.1'

    annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'

}