In this post, we will implement OnClickListener for the ImageView(s) to handle user click.

Modify MyHorizontalLayout.java from the exercise "Implement custom LinearLayout for Gallery-like HorizontalScrollView" to call setOnClickListener() when create ImageView, in getImageView() method. For "Implement Gallery-like HorizontalScrollView" without custom LinearLayout, you can do the same in insertPhoto() method.

package com.example.androidhorizontalscrollviewgallery;

import java.util.ArrayList;

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.util.AttributeSet;

import android.view.View;

import android.widget.ImageView;

import android.widget.LinearLayout;

import android.widget.Toast;

public class MyHorizontalLayout extends LinearLayout {

 Context myContext;

 ArrayList<String> itemList = new ArrayList<String>();

 public MyHorizontalLayout(Context context) {

  super(context);

  myContext = context;

 }

 public MyHorizontalLayout(Context context, AttributeSet attrs) {

  super(context, attrs);

  myContext = context;

 }

 public MyHorizontalLayout(Context context, AttributeSet attrs,

   int defStyle) {

  super(context, attrs, defStyle);

  myContext = context;

 }

 void add(String path){

  int newIdx = itemList.size();

  itemList.add(path);

  addView(getImageView(newIdx));

 }

 ImageView getImageView(final int i){

  Bitmap bm = null;

  if (i < itemList.size()){

   bm = decodeSampledBitmapFromUri(itemList.get(i), 220, 220);

  }

  ImageView imageView = new ImageView(myContext);

     imageView.setLayoutParams(new LayoutParams(220, 220));

     imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);

     imageView.setImageBitmap(bm);

     imageView.setOnClickListener(new OnClickListener(){

   @Override

   public void onClick(View v) {

    Toast.makeText(myContext,

      "Clicked - " + itemList.get(i),

      Toast.LENGTH_LONG).show();

   }});

  return imageView;

 }

 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;

    }

}