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Slider-How to Build Slider in Android App

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With facilitate of Welcome / Intro slide screens in your app you’ll be able to help user demonstrate the key options of the app. During this article, we have a tendency to square measure progressing to find out how to feature a slider to your app wherever user will swipe through few slides before going in app.

To demonstrate, I am creating a simple app that contains few slides with next and skip navigation. The user can navigate through each slide just by swiping or using the next button and can skip the slide whenever wanted and move to the main slide. Generally the introduction slides come for the first time only when the app is installed with the help of Shared preference. But we will explain how to show the intro-slides whenever the app is launched.

Let’s start by creating a new project for the Slider App

1. Creating New Project

  • Create a new project in Android Studio from File ⇒ New Project.When it prompts you to pick the default activity, choose Empty Activity and proceed.

2. Choosing the Colors

It’s completely upto you how you design the screens considering the type of app you are building.For this instance, I’m putting a giant image in centre and few texts below it. At the bottom, number of dots are placed indicating the number of slides it has.

For every screen we want 3 colours i.e background color and 2 dot colours once it’s active / inactive.

  •  Open colors.xml located under res ⇒ values and add the below color values.You can see once adding the colours, I actually have unbroken them into arrays array_dot_active and array_dot_inactive, in order that we will load them simply in our activity.

 Add the below code to colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>

    <!-- Screens background color-->
    <color name="bg_screen1">#f64c73</color>
    <color name="bg_screen2">#20d2bb</color>
    <color name="bg_screen3">#3395ff</color>
    <color name="bg_screen4">#c873f4</color>

    <!-- dots inactive colors -->
    <color name="dot_dark_screen1">#d1395c</color>
    <color name="dot_dark_screen2">#14a895</color>
    <color name="dot_dark_screen3">#2278d4</color>
    <color name="dot_dark_screen4">#a854d4</color>

    <!-- dots active colors -->
    <color name="dot_light_screen1">#f98da5</color>
    <color name="dot_light_screen2">#8cf9eb</color>
    <color name="dot_light_screen3">#93c6fd</color>
    <color name="dot_light_screen4">#e4b5fc</color>

    <array name="array_dot_active">
        <item>@color/dot_light_screen1</item>
        <item>@color/dot_light_screen2</item>
        <item>@color/dot_light_screen3</item>
        <item>@color/dot_light_screen4</item>
    </array>

    <array name="array_dot_inactive">
        <item>@color/dot_dark_screen1</item>
        <item>@color/dot_dark_screen2</item>
        <item>@color/dot_dark_screen3</item>
        <item>@color/dot_dark_screen4</item>
    </array>
</resources>
  • Open strings.xml located under res ⇒ values and add the below string values. Here I’m mentioning a title and outline for every slide.

Add the below code to strings.xml

<resources>
    <string name="app_name">Slider</string>
    <string name="title_activity_welcome">Home Screen</string>
    <string name="next">NEXT</string>
    <string name="skip">SKIP</string>
    <string name="start">GOT IT</string>

    <string name="slide_1_title">Welcome My Cloud Infinity!</string>
    <string name="slide_1_desc">Live to learn and Learn to live!</string>

    <string name="slide_2_title">Android</string>
    <string name="slide_2_desc">Explore the best of Android!</string>

    <string name="slide_3_title">Cloud</string>
    <string name="slide_3_desc">Ride over the clouds and conquer them!</string>

    <string name="slide_4_title">Job Updates</string>
    <string name="slide_4_desc">Not to miss any update get hired!</string> 
<string name="play_again_desc">To see the welcome slider again, goto Settings -> apps -> welcome slider -> clear data</string> <string name="play_again">Play Again</string> </resources>
Note: You can add the text according to your own choice.
  • Open dimens.xml placed under res ⇒ values and add the below values.

Add the code in dimens.xml

<resources>
    <dimen name="activity_horizontal_margin">16dp</dimen>
    <dimen name="activity_vertical_margin">16dp</dimen>
    <dimen name="fab_margin">16dp</dimen>
    <dimen name="dots_height">30dp</dimen>
    <dimen name="dots_margin_bottom">20dp</dimen>
    <dimen name="img_width_height">120dp</dimen>
    <dimen name="slide_title">20dp</dimen>
    <dimen name="slide_desc">16dp</dimen>
    <dimen name="desc_padding">40dp</dimen>
</resources>

  • Also make sure that you have these styles in your styles.xml as the app is crashing because of recent changes in build tools.

Add the below code to styles.xml

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="windowActionBar">false</item>
        <item name="windowNoTitle">true</item>
    </style>

    <style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />

    <style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />

</resources>

3. Creating the Welcome Slides

Now it’s time to create the layouts required for the slider. In total I’m keeping four slides for the intro screen. So we want four separate layout for four slides.The layout of every slide remains a similar except the pictures, text and colours.Alternatively you’ll produce separate Fragment for every slide to possess a lot of management over the UI components displayed within the slide.

  • So quickly produce four xml layouts named welcome_side1.xml, welcome_side2.xml, welcome_side3.xml and welcome_side4.xml below res ⇒ layouts.

 

welcome_slide1.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/bg_screen1">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:gravity="center_horizontal"
        android:orientation="vertical">

        <ImageView
            android:layout_width="@dimen/img_width_height"
            android:layout_height="@dimen/img_width_height"
            android:src="@drawable/image"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/slide_1_title"
            android:textColor="@android:color/white"
            android:textSize="@dimen/slide_title"
            android:textStyle="bold" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:paddingLeft="@dimen/desc_padding"
            android:paddingRight="@dimen/desc_padding"
            android:text="@string/slide_1_desc"
            android:textAlignment="center"
            android:textColor="@android:color/white"
            android:textSize="@dimen/slide_desc" />

    </LinearLayout>
</RelativeLayout>

 

welcome_slide2.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/bg_screen2">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:gravity="center_horizontal"
        android:orientation="vertical">

        <ImageView
            android:layout_width="@dimen/img_width_height"
            android:layout_height="@dimen/img_width_height"
            android:src="@drawable/android" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/slide_2_title"
            android:textColor="@android:color/white"
            android:textSize="@dimen/slide_title"
            android:textStyle="bold" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:paddingLeft="@dimen/desc_padding"
            android:paddingRight="@dimen/desc_padding"
            android:text="@string/slide_2_desc"
            android:textAlignment="center"
            android:textColor="@android:color/white"
            android:textSize="@dimen/slide_desc" />

    </LinearLayout>
</RelativeLayout>

 

welcome_slide3.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/bg_screen3">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:gravity="center_horizontal"
        android:orientation="vertical">

        <ImageView
            android:layout_width="@dimen/img_width_height"
            android:layout_height="@dimen/img_width_height"
            android:src="@drawable/cloud" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/slide_3_title"
            android:textColor="@android:color/white"
            android:textSize="@dimen/slide_title"
            android:textStyle="bold" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:paddingLeft="@dimen/desc_padding"
            android:paddingRight="@dimen/desc_padding"
            android:text="@string/slide_3_desc"
            android:textAlignment="center"
            android:textColor="@android:color/white"
            android:textSize="@dimen/slide_desc" />

    </LinearLayout>
</RelativeLayout>

 

welcome_slide4.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/bg_screen4">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:gravity="center_horizontal"
        android:orientation="vertical">

        <ImageView
            android:layout_width="@dimen/img_width_height"
            android:layout_height="@dimen/img_width_height"
            android:src="@drawable/job" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/slide_4_title"
            android:textColor="@android:color/white"
            android:textSize="@dimen/slide_title"
            android:textStyle="bold" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:paddingLeft="@dimen/desc_padding"
            android:paddingRight="@dimen/desc_padding"
            android:text="@string/slide_4_desc"
            android:textAlignment="center"
            android:textColor="@android:color/white"
            android:textSize="@dimen/slide_desc" />

    </LinearLayout>
</RelativeLayout>
 
  • Once the layouts are ready, create a new activity named WelcomeActivity.java for the welcome slider. Right Click on package New ⇒ Activity ⇒ Empty Activity.
  • Open activity_welcome.xml and modify the code as below. Here I am adding ViewPager for slider, LinearLayout for bottom dots and two buttons for Skip and Next navigation.

Add the below code in activity_welcome.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
tools:showIn="@layout/activity_welcome">

<android.support.v4.view.ViewPager
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />

<LinearLayout
android:id="@+id/layoutDots"
android:layout_width="match_parent"
android:layout_height="@dimen/dots_height"
android:layout_alignParentBottom="true"
android:layout_marginBottom="@dimen/dots_margin_bottom"
android:gravity="center"
android:orientation="horizontal"></LinearLayout>

<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:alpha=".5"
android:layout_above="@id/layoutDots"
android:background="@android:color/white" />

<Button
android:id="@+id/btn_next"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:background="@null"
android:text="@string/next"
android:textColor="@android:color/white" />

<Button
android:id="@+id/btn_skip"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:background="@null"
android:text="@string/skip"
android:textColor="@android:color/white" />

</RelativeLayout>

 

  • Open WelcomeActivity.java and modify the code as below. Here I have taken care of few things
  1. Made the notification bar transparent, so that the view background color can be seen through.
  2. Created a PagerAdapter for the ViewPager and inflated all the layouts we tend to create earlier.
  3. Added click event listener to Skip and Next buttons. If next button is clicked, next slide is going to be shown. If Skip button is clicked, main activity is launched directly.
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.text.Html;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

public class WelcomeActivity extends AppCompatActivity {

    private ViewPager viewPager;
    private MyViewPagerAdapter myViewPagerAdapter;
    private LinearLayout dotsLayout;
    private TextView[] dots;
    private int[] layouts;
    private Button btnSkip, btnNext;
    

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

      

        // Making notification bar transparent
        if (Build.VERSION.SDK_INT >= 21) {
            getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
        }

        setContentView(R.layout.activity_welcome);

        viewPager = (ViewPager) findViewById(R.id.view_pager);
        dotsLayout = (LinearLayout) findViewById(R.id.layoutDots);
        btnSkip = (Button) findViewById(R.id.btn_skip);
        btnNext = (Button) findViewById(R.id.btn_next);


        // layouts of all welcome sliders
        // add few more layouts if you want
        layouts = new int[]{
                R.layout.welcome_slide1,
                R.layout.welcome_slide2,
                R.layout.welcome_slide3,
                R.layout.welcome_slide4};

        // adding bottom dots
        addBottomDots(0);

        // making notification bar transparent
        changeStatusBarColor();

        myViewPagerAdapter = new MyViewPagerAdapter();
        viewPager.setAdapter(myViewPagerAdapter);
        viewPager.addOnPageChangeListener(viewPagerPageChangeListener);

        btnSkip.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                launchHomeScreen();
            }
        });

        btnNext.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // checking for last page
                // if last page home screen will be launched
                int current = getItem(+1);
                if (current < layouts.length) {
                    // move to next screen
                    viewPager.setCurrentItem(current);
                } else {
                    launchHomeScreen();
                }
            }
        });
    }

    private void addBottomDots(int currentPage) {
        dots = new TextView[layouts.length];

        int[] colorsActive = getResources().getIntArray(R.array.array_dot_active);
        int[] colorsInactive = getResources().getIntArray(R.array.array_dot_inactive);

        dotsLayout.removeAllViews();
        for (int i = 0; i < dots.length; i++) {
            dots[i] = new TextView(this);
            dots[i].setText(Html.fromHtml("&#8226;"));
            dots[i].setTextSize(35);
            dots[i].setTextColor(colorsInactive[currentPage]);
            dotsLayout.addView(dots[i]);
        }

        if (dots.length > 0)
            dots[currentPage].setTextColor(colorsActive[currentPage]);
    }

    private int getItem(int i) {
        return viewPager.getCurrentItem() + i;
    }

    private void launchHomeScreen() {
       
        startActivity(new Intent(WelcomeActivity.this, MainActivity.class));
        finish();
    }

    //  viewpager change listener
    ViewPager.OnPageChangeListener viewPagerPageChangeListener = new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
            addBottomDots(position);

            // changing the next button text 'NEXT' / 'GOT IT'
            if (position == layouts.length - 1) {
                // last page. make button text to GOT IT
                btnNext.setText(getString(R.string.start));
                btnSkip.setVisibility(View.GONE);
            } else {
                // still pages are left
                btnNext.setText(getString(R.string.next));
                btnSkip.setVisibility(View.VISIBLE);
            }
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {

        }

        @Override
        public void onPageScrollStateChanged(int arg0) {

        }
    };

    /**
     * Making notification bar transparent
     */
    private void changeStatusBarColor() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            Window window = getWindow();
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            window.setStatusBarColor(Color.TRANSPARENT);
        }
    }

    /**
     * View pager adapter
     */
    public class MyViewPagerAdapter extends PagerAdapter {
        private LayoutInflater layoutInflater;

        public MyViewPagerAdapter() {
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            View view = layoutInflater.inflate(layouts[position], container, false);
            container.addView(view);

            return view;
        }

        @Override
        public int getCount() {
            return layouts.length;
        }

        @Override
        public boolean isViewFromObject(View view, Object obj) {
            return view == obj;
        }


        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            View view = (View) object;
            container.removeView(view);
        }
    }
}
  • Finally open AndroidManifest.xml and build WelcomeActivity as launcher activity. So that it is shown as the first screen in the app.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.sairam.skbday">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name="com.example.sairam.skbday.WelcomeActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name="com.example.sairam.skbday.MainActivity"
            android:label="@string/title_activity_welcome">

        </activity>
    </application>
</manifest>

 

  • Run the app now and have a look!!!

slider Screenshot_20170119-003804 Screenshot_20170119-003828 Screenshot_20170119-003841 Screenshot_20170119-003845

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