A Spinner component with a floating label for Android, similar to EditText components wrapped in a TextInputLayout.

LabelledSpinner.java

/*
 * Copyright 2015 Farbod Salamat-Zadeh
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.yourcompany.yourapp.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.support.annotation.ArrayRes;
import android.support.annotation.ColorRes;
import android.support.annotation.LayoutRes;
import android.support.annotation.StringRes;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.Spinner;
import android.widget.SpinnerAdapter;
import android.widget.TextView;

import com.yourcompany.yourapp.R;

import java.util.ArrayList;

public class LabelledSpinner extends LinearLayout implements AdapterView.OnItemSelectedListener {

    /**
     * The label positioned above the Spinner, similar to the floating
     * label from a {@link android.support.design.widget.TextInputLayout}.
     */
    private TextView mLabel;

    /**
     * The Spinner component used in this layout.
     */
    private Spinner mSpinner;

    /**
     * A thin (1dp thick) divider line positioned below the Spinner,
     * similar to the bottom line in an {@link android.widget.EditText}.
     */
    private View mDivider;
    
    /**
     * The listener that receives notifications when an item in the
     * AdapterView is selected.
     */
    private OnItemChosenListener mOnItemChosenListener;
    
    /**
     * The main color used in the widget (the label color and divider
     * color). This may be updated when XML attributes are obtained and
     * again if the color is set programmatically.
     */
    private int mWidgetColor;


    public LabelledSpinner(Context context) {
        this(context, null);
    }

    public LabelledSpinner(Context context, AttributeSet attrs) {
        super(context, attrs);
        initializeViews(context, attrs);
    }

    private void initializeViews(Context context, AttributeSet attrs) {
        TypedArray typedArray = context.obtainStyledAttributes(
                attrs,
                R.styleable.LabelledSpinner,
                0,
                0);
        String labelText = a.getString(R.styleable.LabelledSpinner_labelText);
        mWidgetColor = typedArray.getColor(R.styleable.LabelledSpinner_widgetColor,
                getResources().getColor(R.color.widget_labelled_spinner));
        typedArray.recycle();

        LayoutInflater inflater =
                (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(R.layout.widget_labelled_spinner, this, true);

        setOrientation(LinearLayout.VERTICAL);
        setLayoutParams(new LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.WRAP_CONTENT));

        mLabel = (TextView) getChildAt(0);
        mLabel.setText(labelText);
        mLabel.setPadding(0, dpToPixels(16), 0, 0);
        mLabel.setTextColor(mWidgetColor);

        mSpinner = (Spinner) getChildAt(1);
        mSpinner.setPadding(0, dpToPixels(8), 0, dpToPixels(8));
        mSpinner.setOnItemSelectedListener(this);

        mDivider = getChildAt(2);
        MarginLayoutParams dividerParams =
                (MarginLayoutParams) mDivider.getLayoutParams();
        dividerParams.rightMargin = dpToPixels(4);
        dividerParams.bottomMargin = dpToPixels(8);
        mDivider.setLayoutParams(dividerParams);
        mDivider.setBackgroundColor(mWidgetColor);
        alignLabelWithSpinnerItem(4);
    }
    
    
    public TextView getLabel() {
        return mLabel;
    }

    public Spinner getSpinner() {
        return mSpinner;
    }

    public View getDivider() {
        return mDivider;
    }


    /**
     * Sets the text the label is to display.
     *
     * @see #setLabelText(int)
     * 
     * @param labelText The CharSequence value to be displayed on the label.
     */
    public void setLabelText(CharSequence labelText) {
        mLabel.setText(labelText);
    }

    /**
     * Sets the text the label is to display.
     * 
     * @see #setLabelText(CharSequence)
     *
     * @param labelTextId The string resource identifier which refers to
     *                    the string value which is to be displayed on
     *                    the label.
     */
    public void setLabelText(@StringRes int labelTextId) {
        mLabel.setText(getResources().getString(labelTextId));
    }
    
    public CharSequence getLabelText() {
        return mLabel.getText();
    }
    
    /**
     * Sets the color to use for the label text and the divider line
     * underneath.
     *
     * @param colorRes The color resource identifier which refers to the
     *                 color that is to be displayed on the widget.
     */
    public void setColor(@ColorRes int colorRes) {
        mLabel.setTextColor(getResources().getColor(colorRes));
        mDivider.setBackgroundColor(getResources().getColor(colorRes));
    }
    
    public int getColor() {
        return mWidgetColor;
    }

    /**
     * Sets the array of items to be used in the Spinner.
     * 
     * @see #setItemsArray(ArrayList)
     * @see #setItemsArray(int, int, int)
     *
     * @param arrayResId The identifier of the array to use as the data
     *                   source (e.g. R.array.myArray)
     */
    public void setItemsArray(@ArrayRes int arrayResId) {
        setItemsArray(
                arrayResId,
                android.R.layout.simple_spinner_item,
                android.R.layout.simple_spinner_dropdown_item
        );
    }
    
    /**
     * Sets the array of items to be used in the Spinner.
     * 
     * @see #setItemsArray(int)
     * @see #setItemsArray(int, int, int)
     *
     * @param arrayList The ArrayList used as the data source
     */
    public void setItemsArray(ArrayList<String> arrayList) {
        ArrayAdapter<String> adapter = new ArrayAdapter<>(
                getContext(),
                android.R.layout.simple_spinner_item,
                arrayList);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        mSpinner.setAdapter(adapter);
    }

    /**
     * A private helper method to set the array of items to be used in the
     * Spinner.
     * 
     * @see #setItemsArray(int)
     * @see #setItemsArray(ArrayList)
     *
     * @param arrayResId The identifier of the array to use as the data
     *                   source (e.g. R.array.myArray)
     * @param spinnerItemRes The identifier of the layout used to create
     *                       views (e.g. R.layout.my_item)
     * @param dropdownViewRes The layout resource to create the drop down
     *                        views (e.g. R.layout.my_dropdown)
     */
    private void setItemsArray(@ArrayRes int arrayResId, @LayoutRes int spinnerItemRes, @LayoutRes int dropdownViewRes) {
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
                getContext(),
                arrayResId,
                spinnerItemRes);
        adapter.setDropDownViewResource(dropdownViewRes);
        mSpinner.setAdapter(adapter);
    }

    /**
     * Sets the Adapter used to provide the data for the Spinner.
     * This would be similar to setting an Adapter for a normal Spinner
     * component.
     *
     * @param adapter The Adapter which would provide data for the Spinner
     */
    public void setCustomAdapter(SpinnerAdapter adapter) {
        mSpinner.setAdapter(adapter);
    }
    
    /**
     * Sets the currently selected item.
     *
     * @param position Index (starting at 0) of the data item to be selected.
     */
    public void setSelection(int position) {
        mSpinner.setSelection(position);
    }


    /**
     * Interface definition for a callback to be invoked when an item in this
     * LabelledSpinner's Spinner view has been selected.
     */
    public interface OnItemChosenListener {

        /**
         * Callback method to be invoked when an item in this LabelledSpinner's
         * spinner view has been selected. This callback is invoked only when
         * the newly selected position is different from the previously selected
         * position or if there was no selected item.
         *
         * @param labelledSpinner The LabelledSpinner where the selection
         *                        happened. This view contains the AdapterView.
         * @param adapterView The AdapterView where the selection happened. Note
         *                    that this AdapterView is part of the LabelledSpinner
         *                    component.
         * @param itemView The view within the AdapterView that was clicked.
         * @param position The position of the view in the adapter.
         * @param id The row id of the item that is selected.
         */
        void onItemChosen(View labelledSpinner, AdapterView<?> adapterView, View itemView, int position, long id);

        /**
         * Callback method to be invoked when the selection disappears from this
         * view. The selection can disappear for instance when touch is activated
         * or when the adapter becomes empty.
         *
         * @param labelledSpinner The LabelledSpinner view that contains the
         *                        AdapterView.
         * @param adapterView The AdapterView that now contains no selected item.
         */
        void onNothingChosen(View labelledSpinner, AdapterView<?> adapterView);
    }

    /**
     * Register a callback to be invoked when an item in this AdapterView has
     * been selected.
     * This would be similar to setting an OnItemSelectedListener for a normal
     * Spinner component.
     *
     * @param onItemChosenListener The callback that will run
     */
    public void setOnItemChosenListener(OnItemChosenListener onItemChosenListener) {
        mOnItemChosenListener = onItemChosenListener;
    }
    
    public OnItemChosenListener getOnItemChosenListener() {
        return mOnItemChosenListener;
    }

    /**
     * Implemented method from {@link android.widget.AdapterView.OnItemSelectedListener}
     */
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        if (mOnItemChosenListener != null) {
            // 'this' refers to this LabelledSpinner component
            mOnItemChosenListener.onItemChosen(this, parent, view, position, id);
        }
    }

    /**
     * Implemented method from {@link android.widget.AdapterView.OnItemSelectedListener}
     */
    @Override
    public void onNothingSelected(AdapterView<?> parent) {
        if (mOnItemChosenListener != null) {
            // 'this' refers to this LabelledSpinner component
            mOnItemChosenListener.onNothingChosen(this, parent);
        }
    }


    /**
     * Adds a 4dp left margin to the label and divider line underneath so that
     * it aligns with the Spinner item text. By default, the additional 4dp
     * margin will not be added.
     * 
     * @see #alignLabelWithSpinnerItem(int)
     *
     * Note: By default, however, a 4dp margin will be added so that the label
     * and divider align correctly with other UI components, such as the label
     * in a {@link android.support.design.widget.TextInputLayout}. This means
     * that if {@param indentLabel} is true, an 8dp left margin will be added
     * (this would be the 4dp margin to align with other UI components with
     * an additional 4dp margin to align the label with the Spinner item text.
     * Also note that if {@param indentLabel} is true, the label and divider
     * will not be aligned with other UI components as they would be 4dp
     * further right from them.
     *
     * @param indentLabel Whether or not the label will be indented
     */
    public void alignLabelWithSpinnerItem(boolean indentLabel) {
        if (indentLabel) {
            alignLabelWithSpinnerItem(8);
        } else {
            alignLabelWithSpinnerItem(4);
        }
    }

    /**
     * A helper method responsible for adding left margins to the label and
     * divider line underneath, used to align these to the start of the Spinner
     * item text.
     * 
     * @see #alignLabelWithSpinnerItem(boolean)
     *
     * @param indentDps The density-independent pixel value for the left margin
     */
    private void alignLabelWithSpinnerItem(int indentDps) {
        MarginLayoutParams labelParams =
                (MarginLayoutParams) mLabel.getLayoutParams();
        labelParams.leftMargin = dpToPixels(indentDps);
        mLabel.setLayoutParams(labelParams);

        MarginLayoutParams dividerParams =
                (MarginLayoutParams) mDivider.getLayoutParams();
        dividerParams.leftMargin = dpToPixels(indentDps);
        mDivider.setLayoutParams(dividerParams);
    }


    /**
     * A helper method responsible for the conversion of dp/dip (density-independent
     * pixel) values to pixels, so that they can be used when setting layout
     * parameters such as margins.
     *
     * @param dps The density-independent pixel value
     * @return The pixel value from the conversion
     */
    private int dpToPixels(int dps) {
        if (dps == 0) {
            return 0;
        }
        final float scale = getResources().getDisplayMetrics().density;
        return (int) (dps * scale + 0.5f);
    }

}

example_usage.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2015 Farbod Salamat-Zadeh

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

         http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:custom="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.yourcompany.yourapp.YourActivity">
    
    <com.yourcompany.yourapp.widget.LabelledSpinner
        android:id="@+id/your_labelled_spinner"
        custom:labelText="@string/your_spinner_label"
        custom:widgetColor="#F44336"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
        
</LinearLayout>

ExampleActivity.java

/*
 * Copyright 2015 Farbod Salamat-Zadeh
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
package com.yourcompany.yourapp;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;

import com.yourcompany.yourapp.widget.LabelledSpinner;


public class ExampleActivity extends AppCompatActivity implements LabelledSpinner.OnItemChosenListener {
     
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.example_usage);
        
        LabelledSpinner yourSpinner = (LabelledSpinner) findViewById(R.id.your_labelled_spinner);
        yourSpinner.setItemsArray(R.array.your_array);
        yourSpinner.setOnItemChosenListener(this);
    }
    
    @Override
    public void onItemChosen(View labelledSpinner, AdapterView<?> adapterView, View itemView, int position, long id) {
        String selectedText = adapterView.getItemAtPosition(position).toString();
        switch (labelledSpinner.getId()) {
            case R.id.your_labelled_spinner:
                // Do something here
                break;
            // If you have multiple LabelledSpinners, you can add more cases here
        }
    }

    @Override
    public void onNothingChosen(View labelledSpinner, AdapterView<?> adapterView) {
        // Do something here
    }
    
}

license-2.0.txt

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values_labelled_spinner.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2015 Farbod Salamat-Zadeh

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

         http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<resources>

    <declare-styleable name="LabelledSpinner" >
        <attr name="labelText" format="string" />
        <attr name="widgetColor" format="color" />
    </declare-styleable>
    
    <color name="widget_labelled_spinner">#6D6D6D</color>

</resources>

widget_labelled_spinner.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright 2015 Farbod Salamat-Zadeh

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

         http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<merge xmlns:android="http://schemas.android.com/apk/res/android">
    <TextView
        android:textSize="12sp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <Spinner
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <View
        android:gravity="start|center_vertical"
        android:layout_width="match_parent"
        android:layout_height="1dp" />
</merge>

@paolorotolo

I have a look at the library I made: https://github.com/FarbodSalamat-Zadeh/LabelledSpinner