Palette

Palette Library:

developer.android.com/topic/libraries/support-library/packages.html#v7-palette

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:id="@+id/root_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.codinginflow.paletteexample.MainActivity">

    <TextView
        android:id="@+id/text_view_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"

        android:text="Title Text"
        android:textColor="@android:color/holo_red_light"
        android:textSize="50sp" />

    <ImageView
        android:id="@+id/image_view"
        android:layout_width="wrap_content"
        android:layout_height="200dp"
        android:scaleType="centerCrop"
        android:src="@drawable/brussels" />

    <TextView
        android:id="@+id/text_view_body"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:text="Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text Body Text "
        android:textColor="@android:color/holo_red_light" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="nextSwatch"
        android:text="Next Swatch" />

</LinearLayout>

package com.codinginflow.paletteexample;

import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.drawable.BitmapDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.graphics.Palette;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private LinearLayout rootLayout;
    private TextView textViewTitle;
    private TextView textViewBody;
    private ImageView imageView;

    private Palette.Swatch vibrantSwatch;
    private Palette.Swatch lightVibrantSwatch;
    private Palette.Swatch darkVibrantSwatch;
    private Palette.Swatch mutedSwatch;
    private Palette.Swatch lightMutedSwatch;
    private Palette.Swatch darkMutedSwatch;

    private int swatchNumber;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        rootLayout = findViewById(R.id.root_layout);
        textViewTitle = findViewById(R.id.text_view_title);
        textViewBody = findViewById(R.id.text_view_body);
        imageView = findViewById(R.id.image_view);

        Bitmap bitmap = ((BitmapDrawable) imageView.getDrawable()).getBitmap();

        Palette.from(bitmap).maximumColorCount(32).generate(new Palette.PaletteAsyncListener() {
            @Override
            public void onGenerated(Palette palette) {
                vibrantSwatch = palette.getVibrantSwatch();
                lightVibrantSwatch = palette.getLightVibrantSwatch();
                darkVibrantSwatch = palette.getDarkVibrantSwatch();
                mutedSwatch = palette.getMutedSwatch();
                lightMutedSwatch = palette.getLightMutedSwatch();
                darkMutedSwatch = palette.getDarkMutedSwatch();
            }
        });
    }

    public void nextSwatch(View v) {
        Palette.Swatch currentSwatch = null;

        switch (swatchNumber) {
            case 0:
                currentSwatch = vibrantSwatch;
                textViewTitle.setText("Vibrant");
                break;
            case 1:
                currentSwatch = lightVibrantSwatch;
                textViewTitle.setText("Light Vibrant");
                break;
            case 2:
                currentSwatch = darkVibrantSwatch;
                textViewTitle.setText("Dark Vibrant");
                break;
            case 3:
                currentSwatch = mutedSwatch;
                textViewTitle.setText("Muted");
                break;
            case 4:
                currentSwatch = lightMutedSwatch;
                textViewTitle.setText("Light Muted");
                break;
            case 5:
                currentSwatch = darkMutedSwatch;
                textViewTitle.setText("Dark Muted");
                break;
        }

        if (currentSwatch != null) {
            rootLayout.setBackgroundColor(currentSwatch.getRgb());
            textViewTitle.setTextColor(currentSwatch.getTitleTextColor());
            textViewBody.setTextColor(currentSwatch.getBodyTextColor());
        } else {
            rootLayout.setBackgroundColor(Color.WHITE);
            textViewTitle.setTextColor(Color.RED);
            textViewBody.setTextColor(Color.RED);
        }

        if (swatchNumber < 5) {
            swatchNumber++;
        } else {
            swatchNumber = 0;
        }
    }
}