TimePickerDialog with fixed android:timePickerMode spinner in Nougat

TimePickerDialogFixedNougatSpinner.java

package my.packagename;

import android.app.TimePickerDialog;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Build;
import android.util.AttributeSet;
import android.widget.TimePicker;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;

/**
 * Workaround for this bug: https://code.google.com/p/android/issues/detail?id=222208
 * In Android 7.0 Nougat, spinner mode for the TimePicker in TimePickerDialog is
 * incorrectly displayed as clock, even when the theme specifies otherwise, such as:
 *
 *  <resources>
 *      <style name="Theme.MyApp" parent="Theme.AppCompat.Light.NoActionBar">
 *          <item name="android:timePickerStyle">@style/Widget.MyApp.TimePicker</item>
 *      </style>
 *
 *      <style name="Widget.MyApp.TimePicker" parent="android:Widget.Material.TimePicker">
 *          <item name="android:timePickerMode">spinner</item>
 *      </style>
 *  </resources>
 *
 * May also pass TimePickerDialog.THEME_HOLO_LIGHT as an argument to the constructor,
 * as this theme has the TimePickerMode set to spinner.
 */
public class TimePickerDialogFixedNougatSpinner extends TimePickerDialog {

    /**
     * Creates a new time picker dialog.
     *
     * @param context the parent context
     * @param listener the listener to call when the time is set
     * @param hourOfDay the initial hour
     * @param minute the initial minute
     * @param is24HourView whether this is a 24 hour view or AM/PM
     */
    public TimePickerDialogFixedNougatSpinner(Context context, OnTimeSetListener listener, int hourOfDay, int minute, boolean is24HourView) {

        super(context, listener, hourOfDay, minute, is24HourView);
        fixSpinner(context, hourOfDay, minute, is24HourView);
    }

    /**
     * Creates a new time picker dialog with the specified theme.
     *
     * @param context the parent context
     * @param themeResId the resource ID of the theme to apply to this dialog
     * @param listener the listener to call when the time is set
     * @param hourOfDay the initial hour
     * @param minute the initial minute
     * @param is24HourView Whether this is a 24 hour view, or AM/PM.
     */
    public TimePickerDialogFixedNougatSpinner(Context context, int themeResId, OnTimeSetListener listener, int hourOfDay, int minute, boolean is24HourView) {

        super(context, themeResId, listener, hourOfDay, minute, is24HourView);
        fixSpinner(context, hourOfDay, minute, is24HourView);
    }

    private void fixSpinner(Context context, int hourOfDay, int minute, boolean is24HourView) {
        if (Build.VERSION.SDK_INT == Build.VERSION_CODES.N) { // fixes the bug in API 24
            try {
                // Get the theme's android:timePickerMode
                final int MODE_SPINNER = 1;
                Class<?> styleableClass = Class.forName("com.android.internal.R$styleable");
                Field timePickerStyleableField = styleableClass.getField("TimePicker");
                int[] timePickerStyleable = (int[]) timePickerStyleableField.get(null);
                final TypedArray a = context.obtainStyledAttributes(null, timePickerStyleable, android.R.attr.timePickerStyle, 0);
                Field timePickerModeStyleableField = styleableClass.getField("TimePicker_timePickerMode");
                int timePickerModeStyleable = timePickerModeStyleableField.getInt(null);
                final int mode = a.getInt(timePickerModeStyleable, MODE_SPINNER);
                a.recycle();
                if (mode == MODE_SPINNER) {
                    TimePicker timePicker = (TimePicker) findField(TimePickerDialog.class, TimePicker.class, "mTimePicker").get(this);
                    Class<?> delegateClass = Class.forName("android.widget.TimePicker$TimePickerDelegate");
                    Field delegateField = findField(TimePicker.class, delegateClass, "mDelegate");
                    Object delegate = delegateField.get(timePicker);
                    Class<?> spinnerDelegateClass;
                    spinnerDelegateClass = Class.forName("android.widget.TimePickerSpinnerDelegate");
                    // In 7.0 Nougat for some reason the timePickerMode is ignored and the delegate is TimePickerClockDelegate
                    if (delegate.getClass() != spinnerDelegateClass) {
                        delegateField.set(timePicker, null); // throw out the TimePickerClockDelegate!
                        timePicker.removeAllViews(); // remove the TimePickerClockDelegate views
                        Constructor spinnerDelegateConstructor = spinnerDelegateClass.getConstructor(TimePicker.class, Context.class, AttributeSet.class, int.class, int.class);
                        spinnerDelegateConstructor.setAccessible(true);
                        // Instantiate a TimePickerSpinnerDelegate
                        delegate = spinnerDelegateConstructor.newInstance(timePicker, context, null, android.R.attr.timePickerStyle, 0);
                        delegateField.set(timePicker, delegate); // set the TimePicker.mDelegate to the spinner delegate
                        // Set up the TimePicker again, with the TimePickerSpinnerDelegate
                        timePicker.setIs24HourView(is24HourView);
                        timePicker.setCurrentHour(hourOfDay);
                        timePicker.setCurrentMinute(minute);
                        timePicker.setOnTimeChangedListener(this);
                    }
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }

    private static Field findField(Class objectClass, Class fieldClass, String expectedName) {
        try {
            Field field = objectClass.getDeclaredField(expectedName);
            field.setAccessible(true);
            return field;
        } catch (NoSuchFieldException e) {} // ignore
        // search for it if it wasn't found under the expected ivar name
        for (Field searchField : objectClass.getDeclaredFields()) {
            if (searchField.getType() == fieldClass) {
                searchField.setAccessible(true);
                return searchField;
            }
        }
        return null;
    }
}

Thanks for your gist @jeffdrg8, It works on Android N and higher, but for me on Android M, implementation of TimePickerDialog.OnTimeSetListener doesn't fire. Any workaround ?

@CyprienGanassali I'm not aware of an issue with Android M. This code should behave as the default TimePickerDialog on all versions of Android except Android N though. The workaround code in fixSpinner() is only executed on Android N to fix this specific issue with that API level. Does your code work as expected on Android M when using the default TimePickerDialog?