Record：Handle onClick for our custom LinearLayout for Gallery-like HorizontalScrollView

The post "Implement Gallery-like HorizontalScrollView" and "Implement custom LinearLayout for Gallery-like HorizontalScrollView" explain how to implement Gallery-like HorizontalScrollView. 

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;   
    }
 
}