How to implement Bottom Sheet fragment in Android

How to implement Bottom Sheet fragment

If you want to show a different type of bottom sheets in the same activity or want to make reusable bottom sheet the should use BottomSheetDialogFragment. The process for this is very similar to that of making a DialogFragment. As in any DialogFragment, Firstly you have to create a layout file for implement Bottom Sheet fragment

bottom_sheet_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:background="@color/white"
        android:padding="16dp">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="16dp"
            android:text="Location:" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Please select a location:"
            android:textColor="@android:color/black"
            android:textSize="16sp" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            android:orientation="horizontal">

            <Button
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginRight="8dp"
                android:layout_weight="1"
                android:background="@android:color/black"
                android:text="Cancel"
                android:textColor="@android:color/white" />

            <Button
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginLeft="8dp"
                android:layout_weight="1"
                android:background="@android:color/black"
                android:text="Get location"
                android:textColor="@android:color/white" />

        </LinearLayout>

    </LinearLayout>

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

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="vertical"

android:background="@color/white"

android:padding="16dp">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginBottom="16dp"

android:text="Location:" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Please select a location:"

android:textColor="@android:color/black"

android:textSize="16sp" />

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginTop="16dp"

android:orientation="horizontal">

<Button

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginRight="8dp"

android:layout_weight="1"

android:background="@android:color/black"

android:text="Cancel"

android:textColor="@android:color/white" />

<Button

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginLeft="8dp"

android:layout_weight="1"

android:background="@android:color/black"

android:text="Get location"

android:textColor="@android:color/white" />

</LinearLayout>

Secondly comes to the JAVA file. For making a modal type of bottom sheet, you will have to extend BottomSheetDialogFragment and set the custom view.

MyBottomSheetFragment.java

public class MyBottomSheetFragment extends BottomSheetDialogFragment {
 
    @Override
    public void setupDialog(Dialog dialog, int style) {
        super.setupDialog(dialog, style);
 
        //Set the custom view
        View view = LayoutInflater.from(getContext()).inflate(R.layout.fragment_bottom_sheet, null);
        dialog.setContentView(view);
    }
}

public class MyBottomSheetFragment extends BottomSheetDialogFragment {

@Override

public void setupDialog(Dialog dialog, int style) {

super.setupDialog(dialog, style);

//Set the custom view

View view = LayoutInflater.from(getContext()).inflate(R.layout.fragment_bottom_sheet, null);

dialog.setContentView(view);

}

MainActivity.java

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        MyBottomSheetFragment fragment = new MyBottomSheetFragment();
        fragment.show(getSupportFragmentManager(), "TAG");

    }
}

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

MyBottomSheetFragment fragment = new MyBottomSheetFragment();

fragment.show(getSupportFragmentManager(), "TAG");

}

After that, When you call show() method it just spread the bottom sheet.

Listening to state changes in BottomSheetDialogFragment

To listen for state changes in DialogFragment you will first have to get access to the BottomSheetBehaviour instance. Here is how you do it.

public class MyBottomSheetFragment extends BottomSheetDialogFragment {
 
    @Override
    public void setupDialog(Dialog dialog, int style) {
        super.setupDialog(dialog, style);
        //Set the custom view
        View view = LayoutInflater.from(getContext()).inflate(R.layout.fragment_bottom_sheet, null);
        dialog.setContentView(view);

        CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) ((View) view.getParent()).getLayoutParams();
        CoordinatorLayout.Behavior behavior = params.getBehavior();
 
        if (behavior != null && behavior instanceof BottomSheetBehavior) {
            ((BottomSheetBehavior) behavior).setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
                @Override
                public void onStateChanged(@NonNull View bottomSheet, int newState) {
                    String state = "";
 
                    switch (newState) {
                        case BottomSheetBehavior.STATE_DRAGGING: {
                            state = "DRAGGING";
                            break;
                        }
                        case BottomSheetBehavior.STATE_SETTLING: {
                            state = "SETTLING";
                            break;
                        }
                        case BottomSheetBehavior.STATE_EXPANDED: {
                            state = "EXPANDED";
                            break;
                        }
                        case BottomSheetBehavior.STATE_COLLAPSED: {
                            state = "COLLAPSED";
                            break;
                        }
                        case BottomSheetBehavior.STATE_HIDDEN: {
                            dismiss();
                            state = "HIDDEN";
                            break;
                        }
                    }
 
                    Toast.makeText(getContext(), "Bottom Sheet State Changed to: " + state, Toast.LENGTH_SHORT).show();
                }
 
                @Override
                public void onSlide(@NonNull View bottomSheet, float slideOffset) {
                }
            });
    }
}

public class MyBottomSheetFragment extends BottomSheetDialogFragment {

@Override

public void setupDialog(Dialog dialog, int style) {

super.setupDialog(dialog, style);

//Set the custom view

View view = LayoutInflater.from(getContext()).inflate(R.layout.fragment_bottom_sheet, null);

dialog.setContentView(view);

CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) ((View) view.getParent()).getLayoutParams();

CoordinatorLayout.Behavior behavior = params.getBehavior();

if (behavior != null && behavior instanceof BottomSheetBehavior) {

((BottomSheetBehavior) behavior).setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {

@Override

public void onStateChanged(@NonNull View bottomSheet, int newState) {

String state = "";

switch (newState) {

case BottomSheetBehavior.STATE_DRAGGING: {

state = "DRAGGING";

break;

}

case BottomSheetBehavior.STATE_SETTLING: {

state = "SETTLING";

break;

}

case BottomSheetBehavior.STATE_EXPANDED: {

state = "EXPANDED";

break;

}

case BottomSheetBehavior.STATE_COLLAPSED: {

state = "COLLAPSED";

break;

}

case BottomSheetBehavior.STATE_HIDDEN: {

dismiss();

state = "HIDDEN";

break;

}

Toast.makeText(getContext(), "Bottom Sheet State Changed to: " + state, Toast.LENGTH_SHORT).show();

}

@Override

public void onSlide(@NonNull View bottomSheet, float slideOffset) {

}

});

}

Make sure to dismiss the dialog when the state is STATE_HIDDEN, the bottom sheet might have disappeared (gone into the hidden state) but since this is a DialogFragment, the dialog itself is still visible to the user.

In conclusion, how the bottom sheet looks like:

Anand Kashyap 30 September 2019

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How to implement Bottom Sheet fragment in Android

How to implement Bottom Sheet fragment

Listening to state changes in BottomSheetDialogFragment

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