Dark theme android app

SIMPLEST SOLUTION

You can enable/disable dark theme just by:

1. enable dark theme:

   AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES)
   

2. forcefully disable dark theme:

   AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)
   

3. set app theme based on mobile settings of dark mode, i.e. if dark mode is enabled then the theme will be set to a dark theme, if not then the default theme, but this will only work in version >= Android version Q

   AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM)
   

Notes:

1. Your base theme for app/activity should be

"Theme.AppCompat.DayNight"

like

<style name="DarkTheme" parent="Theme.AppCompat.DayNight">
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
</style>

2. Your res folder's names would end with -night so that different colors and images you can set for day and night themes like

drawable & drawable-night,
values & values-night

Replace these values in your colors.xml

<color name="colorPrimary">#101010</color>
<color name="colorPrimaryDark">#000000</color>

This would be enough to change the Toolbar's color.

---

If you don't want to change the whole app primary color (which seems it is what you were trying to do in the first place), try creating a new Toolbar by:

Add this to your app's build.gradle

compile 'com.android.support:design:23.1.1'

Add this to your main layout (activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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"
    android:fitsSystemWindows="true"
    tools:context="mx.evin.apps.startingtemplate.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.v7.widget.Toolbar
            android:id="@+id/a_main_toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@android:color/black"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

    </android.support.design.widget.AppBarLayout>

</android.support.design.widget.CoordinatorLayout>

Set this in your styles (styles.xml):

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

And set the new toolbar (MainActivity.java).

Toolbar toolbar = (Toolbar) findViewById(R.id.a_main_toolbar);
setSupportActionBar(toolbar);