Search ListView won't work

Question

I've been working on an Android project, which uses three different activities. They're basically all Listviews. The ListView isn't hardcoded in the project, it is being fetched from a DB. I'm having trouble trying to connect the Search function to the listview. So far I've seen lots of tutorials teaching to create an ArrayAdapter to communicate with a hard-coded Listview, but I can't seem to figure out how to connect it to search from a SQL-based listview. I found a somewhat similar question from HERE, tried to create an extra ArrayAdapter, but got nowhere. Result is , when I click on the search bar, and try to type any letters to see an actual result, it doesn't do anything.

Here's my MainActivity

package com.example.ragnar.sortiment;

import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SearchView;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class SortimentActivity extends AppCompatActivity {

List<Sortiment> sortimentMap = new ArrayList<>();
SortimentAdapter sortimentAdapter;
Context thisContext;
EditText edtSearch;
ListView myListView;
ArrayAdapter<String> searchAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sortiment);

    Integer selectedStoreId = getIntent().getExtras().getInt("store_id");


    edtSearch = (EditText)findViewById(R.id.edtSearch);
    myListView = (ListView) findViewById(R.id.storesListView);
    searchAdapter = new ArrayAdapter<String>(this,R.layout.list_item);
    thisContext = this;

    edtSearch.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
            SortimentActivity.this.searchAdapter.getFilter().filter(charSequence);
        }

        @Override
        public void afterTextChanged(Editable editable) {

        }
    });


    GetSortimentForStore retrieveData = new GetSortimentForStore();
    retrieveData.execute(selectedStoreId);

}

private class GetSortimentForStore extends AsyncTask<Integer,String,String> {

    String msg = "";
    // JDBC Driver name and database URL
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    // Example 10.20.30.40:3306
    static final String DB_URL = "jdbc:mysql://" +
            DbStrings.DATABASE_URL + "/" +
            DbStrings.DATABASE_NAME;

    @Override
    protected void onPreExecute() {

        //progressTextView.setText("Ühendan andmebaasi...");
    }

    @Override
    protected String doInBackground(Integer... selectedStores) {

        Connection conn = null;
        Statement stmt = null;

        try {
            Integer selectedStore = selectedStores[0];
            Class.forName(JDBC_DRIVER);
            conn = DriverManager.getConnection(DB_URL, DbStrings.USERNAME, DbStrings.PASSWORD);

            stmt = conn.createStatement();
            String sql = "select id, store_id, name, ean, description from myproject.sortiments WHERE store_id = " + selectedStore;
            ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                Sortiment newSortiment = new Sortiment();
                newSortiment.id = rs.getInt("id");
                newSortiment.name = rs.getString("name");
                newSortiment.store_id = rs.getInt("store_id");
                newSortiment.ean = rs.getString("ean");
                newSortiment.description = rs.getString("description");
                sortimentMap.add(newSortiment);
            }

            rs.close();
            stmt.close();
            conn.close();

        } catch (SQLException connError) {
            msg = "An exception was thrown for JDBC.";
            connError.printStackTrace();
        } catch (ClassNotFoundException e) {
            msg = "A class not found exception was thrown.";
            e.printStackTrace();
        } finally {

            try {
                if (stmt != null) {
                    stmt.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }

            try {
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }

        }

        return null;
    }

    @Override
    protected void onPostExecute(String msg) {
        sortimentAdapter = new SortimentAdapter(thisContext, sortimentMap);
        myListView.setAdapter(sortimentAdapter);

    }

}
}

The Adapter for ListViews

package com.example.user.sortment;

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.TextView;

import java.util.List;

/**
 * Created by User on 11.05.2018
 */

public class SortmentAdapter extends BaseAdapter implements Filterable {

LayoutInflater mInflator;
List<Sortiment> map;

public void filterResults(CharSequence filter){

}

public SortimentAdapter(Context c, List<Sortiment> inputMap) {
    mInflator = (LayoutInflater)             
c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    map = inputMap;
}

@Override
public int getCount() {
    return map.size();
}

@Override
public Object getItem(int position) {
    return map.get(position);
}

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

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

    View v = mInflator.inflate(R.layout.item_layout,null);
    TextView nameTextView = (TextView) v.findViewById(R.id.nameTextView);
    TextView priceTextView = (TextView) v.findViewById(R.id.priceTextView);

    Sortiment viewObject = map.get(position);
    nameTextView.setText(viewObject.name);
    //priceTextView.setText(String.format("%.0f", prices.get(position)));
    priceTextView.setText(viewObject.ean.toString());

    return v;
}

@Override
public Filter getFilter() {
    return null;
}
}

And AndroidManifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.user.sortment">

<uses-permission android:name="android.permission.INTERNET" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".StoreActivity" />
    <activity android:name=".SortmentActivity"
        android:windowSoftInputMode="stateHidden">
    </activity>
</application>

</manifest>

And my .xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout         
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:context="com.example.user.sortment.MainActivity">

<EditText
    android:id="@+id/edtSearch"
    android:hint="Search.."
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />


<ListView
    android:id="@+id/storesListView"
    android:layout_width="361dp"
    android:layout_height="447dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/progressTextView"
    app:layout_constraintBottom_toBottomOf="parent"
    android:layout_marginBottom="16dp"
    app:layout_constraintHorizontal_bias="0.571"
    tools:layout_editor_absoluteY="48dp" />

<TextView
    android:id="@+id/textView3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.077"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.081" />



<TextView
    android:id="@+id/franchiseTextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:text="TOODE"
    android:textSize="14sp"
    app:layout_constraintBottom_toTopOf="@+id/storesListView"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.05"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.8" />


<TextView
    android:id="@+id/EANtextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:text="EAN"
    app:layout_constraintBottom_toTopOf="@+id/storesListView"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.841"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.8" />

</android.support.constraint.ConstraintLayout>

You might want to migrate to RecyclerView and Use a architecture component like Room (ORM) and LiveData and SearchView. It will more performant and easier to setup. https://stackoverflow.com/questions/49667483/filtering-recyclerviews-list-with-livedata-content-using-searchview — Timo, Aug 08 '18 at 07:54

score 2 · Answer 1 · answered Aug 08 '18 at 07:56

You need to create a custom filter inside your ListView adapter:

private class ItemFilter extends Filter {
    @Override
    protected FilterResults performFiltering(CharSequence constraint) {

        String filterString = constraint.toString().toLowerCase();

        FilterResults results = new FilterResults();

        final List<Sortiment> list = map;

        int count = list.size();
        final ArrayList<Sortiment> nlist = new ArrayList<Sortiment>(count);

        String filterableString ;

        for (int i = 0; i < count; i++) {
            filterableString = list.get(i);
            if (viewObject.name.toLowerCase().contains(filterString)) {
                nlist.add(filterableString);
            }
        }

        results.values = nlist;
        results.count = nlist.size();

        return results;
    }

    @SuppressWarnings("unchecked")
    @Override
    protected void publishResults(CharSequence constraint, FilterResults results) {
        filteredData = (ArrayList<Sortiment>) results.values;
        notifyDataSetChanged();
    }

}

And then in your getFilter(..) method of your ListView adapter, you need to return the custom filter object that you just created above inside your Adapter Class like this:

//Instance variable in your listView Adapter class
private ItemFilter mFilter = new ItemFilter();

@Override
public Filter getFilter() {
    return mFilter;
}

P.S: You also need to display a loader and disable Your search EditText field while the data is being fetched from the server.

I hope this helps.

Search ListView won't work

1 Answers1