Android Custom ListView Search/Filter and ItemClickListener tutorial.

In this piece we see how to search/filter a ListView then handle the itemClick events for the searched cardviews.

Many a times you want to search data. Searching data in a fundamntal thing in working with computers.

We human beings can only work with a small subset of data at a given time.

Searching helps us in this as we filter only the required data and work with it.

In this tutorial we see how to search/filter a custom listview with images and text and handle onItemClickListener after searching.

Let’s go.

1. Create Basic Activity Project

  1. The very first move is to create a new project in android studio. Go to File –> New Project.
  2. Type the application name and choose the company name.
    New Project Dialog
  3. Choose minimum SDK.
    Choose minimum SDK
  4. Choose Basic activity.
    Choose Empty Activity
  5. Click Finish.
    Finish

Basic activity will have a toolbar and floating action button already added in the layout

Normally two layouts get generated with this option:

No. Name Type Description
1. activity_main.xml XML Layout Will get inflated into MainActivity Layout.Typically contains appbarlayout with toolbar.Also has a floatingactionbutton.
2. content_main.xml XML Layout Will be included into activity_main.xml.You add your views and widgets here.
3. MainActivity.java Class Main Activity.

In this example I used a basic activity.

The activity will automatically be registered in the android_manifest.xml. Android Activities are components and normally need to be registered as an application component.

If you’ve created yours manually then register it inside the <application>...<application> as following, replacing the MainActivity with your activity name:


        <activity android_name=".MainActivity">

            <intent-filter>

                <action android_name="android.intent.action.MAIN" />

                <category android_name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

You can see that one action and category are specified as intent filters. The category makes our MainActivity as launcher activity. Launcher activities get executed first when th android app is run.

Advantage of Creating Basic Activity project

You can optionally choose empty activity over basic activity for this project.

However basic activity has the following advantages:

No. Advantage
1. Provides us a readymade toolbar which gives us actionbar features yet easily customizable
2. Provides us with appbar layout which implements material design appbar concepts.
3. Provides a FloatinActionButton which we can readily use to initiate quick actions especially in examples like these.
4. Decouples our custom content views and widgets from the templating features like toolbar.

Generated Project Structure

AndroidStudio will generate for you a project with default configurations via a set of files and directories.

Here are the most important of them:

No. File Major Responsibility
1. build/ A directory containing resources that have been compiled from the building of application and the classes generated by android tools. Such a tool is the R.java file. R.java file normally holds the references to application resources.
2. libs/ To hold libraries we use in our project.
3. src/main/ To hold the source code of our application.This is the main folder you work with.
4. src/main/java/ Contains our java classes organized as packages.
5. src/main/res/ Contains our project resources folders as follows.
6. src/main/res/drawable/ Contains our drawable resources.
7. src/main/res/layout/ Contains our layout resources.
8. src/main/res/menu/ Contains our menu resources XML code.
9. src/main/res/values/ Contains our values resources XML code.These define sets of name-value pairs and can be strings, styles and colors.
10. AndroidManifest.xml This file gets autogenerated when we create an android project.It will define basic information needed by the android system like application name,package name,permissions,activities,intents etc.
11. build.gradle Gradle Script used to build the android app.

3. Create User Interface

User interfaces are typically created in android using XML layouts as opposed by direct java coding.

This is an example fo declarative programming.

######### Advantages of Using XML over Java

No. Advantage
1. Declarative creation of widgets and views allows us to use a declarative language XML which makes is easier.
2. It’s easily maintanable as the user interface is decoupled from your Java logic.
3. It’s easier to share or download code and safely test them before runtime.
4. You can use XML generated tools to generate XML

Here are our layouts for this project:

(a). activity_main.xml
  • This layout gets inflated to MainActivity user interface.
  • It includes the content_main.xml.

Here are some of the widgets, views and viewgroups that get employed”

No. View/ViewGroup Package Role
1. CordinatorLayout android.support.design.widget Super-powered framelayout that provides our application’s top level decoration and is also specifies interactions and behavioros of all it’s children.
2. AppBarLayout android.support.design.widget A LinearLayout child that arranges its children vertically and provides material design app bar concepts like scrolling gestures.
3. ToolBar <android.support.v7.widget A ViewGroup that can provide actionbar features yet still be used within application layouts.
4. FloatingActionButton android.support.design.widget An circular imageview floating above the UI that we can use as buttons.
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 
    
    
    android_layout_width="match_parent"
    android_layout_height="match_parent"
    android_fitsSystemWindows="true"
    tools_context="com.tutorials.hp.lvfilter.MainActivity">

    <android.support.design.widget.AppBarLayout
        android_layout_width="match_parent"
        android_layout_height="wrap_content"
        android_theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android_id="@+id/toolbar"
            android_layout_width="match_parent"
            android_layout_height="?attr/actionBarSize"
            android_background="?attr/colorPrimary"
            app_popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_main" />

    <android.support.design.widget.FloatingActionButton
        android_id="@+id/fab"
        android_layout_width="wrap_content"
        android_layout_height="wrap_content"
        android_layout_gravity="bottom|end"
        android_layout_margin="@dimen/fab_margin"
        android_src="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>
(b). content_main.xml

This layout gets included in your activity_main.xml.

We are going to add a ListView and SearchView here. We’ll arrange them in a vertical linear layout with searchview on top of ListView.

Users will use the SearchView to search/filter the ListView.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 
    
    
    android_layout_width="match_parent"
    android_layout_height="match_parent"
    android_paddingBottom="@dimen/activity_vertical_margin"
    android_paddingLeft="@dimen/activity_horizontal_margin"
    android_paddingRight="@dimen/activity_horizontal_margin"
    android_paddingTop="@dimen/activity_vertical_margin"
    app_layout_behavior="@string/appbar_scrolling_view_behavior"
    tools_context="com.tutorials.hp.lvfilter.MainActivity"
    tools_showIn="@layout/activity_main">

    <android.support.v7.widget.SearchView
        android_id="@+id/mSearch"
        android_layout_width="match_parent"
        android_layout_height="50dp"
        app_defaultQueryHint="Search.."
        />
    <ListView
        android_layout_width="wrap_content"
        android_layout_height="wrap_content"
        android_id="@+id/lv"
        android_layout_below="@+id/mSearch"
        android_layout_alignParentLeft="true"
        android_layout_alignParentStart="true" />
</RelativeLayout>
(c). model.xml

This layout will define our custom rows in our ListView.

This a custom listview we are searching so we need a model layout to model each row.

In this case we have image and text.

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView 
    android_orientation="horizontal" android_layout_width="match_parent"
    
    android_layout_margin="10dp"
    card_view_cardCornerRadius="10dp"
    card_view_cardElevation="10dp"

    android_layout_height="wrap_content">

    <RelativeLayout
        android_layout_width="match_parent"
        android_layout_height="match_parent">

        <ImageView
            android_layout_width="wrap_content"
            android_layout_height="wrap_content"
            android_id="@+id/movieImage"
            android_padding="10dp"
            android_src="@drawable/ghost" />

        <TextView
            android_layout_width="wrap_content"
            android_layout_height="wrap_content"
            android_textAppearance="?android:attr/textAppearanceLarge"
            android_text="Name"
            android_id="@+id/nameTxt"
            android_padding="10dp"
            android_textColor="@color/colorAccent"
            android_layout_below="@+id/movieImage"
            android_layout_alignParentLeft="true"
             />

        <TextView
            android_layout_width="wrap_content"
            android_layout_height="wrap_content"
            android_textAppearance="?android:attr/textAppearanceLarge"
            android_text=" John Doe a former FBI Agent and now Physics teacher .is wrongly accussed of murdering an innocent child.He makes it his business to find the bad guys who did taht.He convinces hacker Aram to join him.....
            "
            android_id="@+id/descTxt"
            android_padding="10dp"
            android_layout_below="@+id/nameTxt"
            android_layout_alignParentLeft="true"
            />

        <TextView
            android_layout_width="wrap_content"
            android_layout_height="wrap_content"
            android_textAppearance="?android:attr/textAppearanceMedium"
            android_text="TV Show"
            android_id="@+id/posTxt"
            android_padding="10dp"

            android_layout_below="@+id/movieImage"
            android_layout_alignParentRight="true" />

        <CheckBox
            android_layout_width="wrap_content"
            android_layout_height="wrap_content"
            android_id="@+id/chk"
            android_layout_alignParentRight="true"
            />

    </RelativeLayout>
</android.support.v7.widget.CardView>

Let’s now jump to our Java classes.

4. Movie.java

This is basically our POJO class.
We will be showing lists of movies in our ListView.

package com.tutorials.hp.lvfilter;

public class Movie {

    private String name;
    private int image;

    public Movie(String name, int image) {
        this.name = name;
        this.image = image;
    }

    public String getName() {
        return name;
    }

    public int getImage() {
        return image;
    }
}

5. ItemClickListener.java

This is an interface that defines us our event handler signature.

package com.tutorials.hp.lvfilter;

import android.view.View;

public interface ItemClickListener {

    void onItemClick(View v);
}

6. MyViewHolder.java

This is our view holder class.

The class will hold our imageview and textview so that they can be reused by the adapter.

package com.tutorials.hp.lvfilter;

import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class MyViewHolder implements View.OnClickListener {

    ImageView img;
    TextView nameTxt;
    ItemClickListener itemClickListener;

    public MyViewHolder(View v) {
        img= (ImageView) v.findViewById(R.id.movieImage);
        nameTxt= (TextView) v.findViewById(R.id.nameTxt);

        v.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        this.itemClickListener.onItemClick(v);
    }

    public void setItemClickListener(ItemClickListener ic)
    {
        this.itemClickListener=ic;
    }
}

6. MyAdapter.java

This is our adapter class. It derives from android.widget.BaseAdapter.

This class will bind our data to our inflated model.xml view object. It will also inflate that layout in the first place.

This class will also implement Filterable interface and override the getFilter() method.

package com.tutorials.hp.lvfilter;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.Toast;

import java.util.ArrayList;

public class MyAdapter extends BaseAdapter implements Filterable {

    Context c;
    ArrayList<Movie> movies;
    LayoutInflater inflater;

    ArrayList<Movie> filterList;
    CustomFilter filter;

    public MyAdapter(Context c, ArrayList<Movie> movies) {
        this.c = c;
        this.movies = movies;
        this.filterList=movies;
    }

    //TOTLA NUM OF MOVIES
    @Override
    public int getCount() {
        return movies.size();
    }

    //GET A SINGLE MOVIE
    @Override
    public Object getItem(int position) {
        return movies.get(position);
    }

    //IDENTITDIER
    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        if(inflater==null)
        {
            inflater= (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }

        //PERFORM INFLATION
        if(convertView==null)
        {
            convertView=inflater.inflate(R.layout.model,null);
        }

        //BIND DATA TO VIEWS
        MyViewHolder holder=new MyViewHolder(convertView);
        holder.nameTxt.setText(movies.get(position).getName());
        holder.img.setImageResource(movies.get(position).getImage());

        holder.setItemClickListener(new ItemClickListener() {
            @Override
            public void onItemClick(View v) {
                Toast.makeText(c,movies.get(position).getName(),Toast.LENGTH_SHORT).show();
            }
        });

        //RETURN A ROW
        return convertView;
    }

    @Override
    public Filter getFilter() {

        if(filter==null)
        {
            filter=new CustomFilter(filterList,this);
        }

        return filter;
    }
}

7. CustomFilter.java

This is the class that will implement our actual search. We will be searching with the contains() method of a String class.

This class derives from android.widget.Filter.

package com.tutorials.hp.lvfilter;

import android.widget.Filter;

import java.util.ArrayList;

public class CustomFilter extends Filter {

    ArrayList<Movie> filterList;
    MyAdapter adapter;

    public CustomFilter(ArrayList<Movie> filterList, MyAdapter adapter) {
        this.filterList = filterList;
        this.adapter = adapter;
    }

    //FILTERING
    @Override
    protected FilterResults performFiltering(CharSequence constraint) {

        //RESULTS
        FilterResults results=new FilterResults();

        //VALIDATION
        if(constraint != null && constraint.length()>0)
        {

            //CHANGE TO UPPER FOR CONSISTENCY
            constraint=constraint.toString().toUpperCase();

            ArrayList<Movie> filteredMovies=new ArrayList<>();

            //LOOP THRU FILTER LIST
            for(int i=0;i<filterList.size();i++)
            {
                //FILTER
                if(filterList.get(i).getName().toUpperCase().contains(constraint))
                {
                    filteredMovies.add(filterList.get(i));
                }
            }

            results.count=filteredMovies.size();
            results.values=filteredMovies;
        }else
        {
            results.count=filterList.size();
           results.values=filterList;
        }

        return results;
    }

    //PUBLISH RESULTS

    @Override
    protected void publishResults(CharSequence constraint, FilterResults results) {

        adapter.movies= (ArrayList<Movie>) results.values;
        adapter.notifyDataSetChanged();

    }
}

8. MainActivity.java

This is our main activity class. It derives from android.app.AppCompatActivity class.

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