थीम और शैलियाँ

<!-- res/values/themes.xml -->
<resources>
    <style name="Theme.MyApp" parent="Theme.Material3.DayNight.NoActionBar">
        <!-- Color -->
        <item name="colorPrimary">@color/primary</item>
        <item name="colorOnPrimary">@color/on_primary</item>
        <item name="colorSecondary">@color/secondary</item>
        <item name="colorSurface">@color/surface</item>
        <item name="colorBackground">@color/background</item>

        <!-- Typography -->
        <item name="textAppearanceBodyMedium">@style/BodyMedium</item>

        <!-- Shape -->
        <item name="shapeAppearanceMediumComponent">@style/Shape.Medium</item>
    </style>
</resources>

<!-- res/values/colors.xml -->
<resources>
    <color name="primary">#6750A4</color>
    <color name="on_primary">#FFFFFF</color>
    <color name="secondary">#625B71</color>
    <color name="on_secondary">#FFFFFF</color>
    <color name="surface">#FFFBFE</color>
    <color name="background">#FFFBFE</color>
    <color name="error">#B3261E</color>
</resources>

<!-- res/values-night/colors.xml  (night override) -->
<resources>
    <color name="primary">#D0BCFF</color>
    <color name="on_primary">#381E72</color>
    <color name="surface">#1C1B1F</color>
    <color name="background">#1C1B1F</color>
</resources>

// Switch dark mode programmatically:
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES)   // force dark
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)    // force light
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM) // auto

<TextView
    android:textAppearance="?attr/textAppearanceDisplayLarge"
    android:text="Big Title" />

<TextView
    android:textAppearance="?attr/textAppearanceHeadlineMedium"
    android:text="Section Header" />

<TextView
    android:textAppearance="?attr/textAppearanceBodyMedium"
    android:text="Body text content here" />

<TextView
    android:textAppearance="?attr/textAppearanceLabelSmall"
    android:text="Caption" />

<!-- res/font/my_font.xml — font family -->
<font-family xmlns:app="http://schemas.android.com/apk/res-auto">
    <font app:fontStyle="normal" app:fontWeight="400"
          app:font="@font/roboto_regular" />
    <font app:fontStyle="normal" app:fontWeight="700"
          app:font="@font/roboto_bold" />
</font-family>

<!-- Apply to a style: -->
<style name="Theme.MyApp" parent="...">
    <item name="android:fontFamily">@font/my_font</item>
</style>

<!-- AndroidManifest.xml -->
<application
    android:theme="@style/Theme.MyApp">

    <!-- Different theme for splash screen -->
    <activity
        android:name=".SplashActivity"
        android:theme="@style/Theme.MyApp.Splash" />

    <activity
        android:name=".MainActivity" />
</application>

fun getColorFromTheme(context: Context, attrResId: Int): Int {
    val typedValue = TypedValue()
    context.theme.resolveAttribute(attrResId, typedValue, true)
    return typedValue.data
}

// Usage:
val primaryColor = getColorFromTheme(this, com.google.android.material.R.attr.colorPrimary)
binding.myView.setBackgroundColor(primaryColor)