Creating a HorizontalScrollView of Images like Galery from Drawable

First, we have to create layout for display images in the horizontal view

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <HorizontalScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
        <LinearLayout
            android:id="@+id/mygallery"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            />
    </HorizontalScrollView>

</LinearLayout>

I have created a Horizontal Scroll view inside the Linear layout.Save the code in activity_main.xml file.


Creating a activity file( MainActivity)..

write the following code inside oncreate() method to add all the image drawble to the layout


       //get the linear layout from activity_main.xml
       LinearLayout myGallery = (LinearLayout) findViewById(R.id.mygallery);
     
        //store image ids in array
        int[] imgIds = { R.drawable.ic_launcher, R.drawable.ic_launcher,
                R.drawable.ic_launcher, R.drawable.ic_launcher,
                R.drawable.ic_launcher, R.drawable.ic_launcher };

        //looping through the array
        for (int i = 0; i < imgIds.length; i++) {
            //create bitmap from the drawable resources using id
            Bitmap bitmap = BitmapFactory.decodeResource(getResources(),
                    imgIds[i]);

            // add the bit map to the layout
            myGallery.addView(insertPhoto(bitmap));
        }

To add the images to galary, you have to create insert function

View insertPhoto(Bitmap image) {
        //create layout programatically
        LinearLayout layout = new LinearLayout(getApplicationContext());
        layout.setLayoutParams(new LayoutParams(250, 250));
        layout.setGravity(Gravity.CENTER);

        ImageView imageView = new ImageView(getApplicationContext());
        imageView.setLayoutParams(new LayoutParams(220, 220));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setImageBitmap(image);

        imageView.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

            }
        });

        layout.addView(imageView);
        return layout;
    }



Full source code is shown below.

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.Gravity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.Toast;

public class MainActivity extends Activity {

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

        LinearLayout myGallery = (LinearLayout) findViewById(R.id.mygallery);

        int[] imgIds = { R.drawable.ic_launcher, R.drawable.ic_launcher,
                R.drawable.ic_launcher, R.drawable.ic_launcher,
                R.drawable.ic_launcher, R.drawable.ic_launcher };

        for (int i = 0; i < imgIds.length; i++) {

            Bitmap bitmap = BitmapFactory.decodeResource(getResources(),
                    imgIds[i]);
            myGallery.addView(insertPhoto(bitmap));
        }
    }

    View insertPhoto(Bitmap image) {

        LinearLayout layout = new LinearLayout(getApplicationContext());
        layout.setLayoutParams(new LayoutParams(250, 250));
        layout.setGravity(Gravity.CENTER);

        ImageView imageView = new ImageView(getApplicationContext());
        imageView.setLayoutParams(new LayoutParams(220, 220));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setImageBitmap(image);

        imageView.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

            }
        });

        layout.addView(imageView);
        return layout;
    }

    public Bitmap decodeSampledBitmapFromUri(String path, int reqWidth,
            int reqHeight) {
        Bitmap bm = null;

        // First decode with inJustDecodeBounds=true to check dimensions
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(path, options);

        // Calculate inSampleSize
        options.inSampleSize = calculateInSampleSize(options, reqWidth,
                reqHeight);

        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;
        bm = BitmapFactory.decodeFile(path, options);

        return bm;
    }

    public int calculateInSampleSize(

    BitmapFactory.Options options, int reqWidth, int reqHeight) {
        // Raw height and width of image
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {
            if (width > height) {
                inSampleSize = Math.round((float) height / (float) reqHeight);
            } else {
                inSampleSize = Math.round((float) width / (float) reqWidth);
            }
        }

        return inSampleSize;
    }

}