Our code example for today is about a very useful Android widget called AutocompleteTextView. This widget looks like an EditText but shows completion suggestions automatically while the user is typing.
The list of suggestions is displayed in a drop down menu from which the user can choose an item to replace the content of the edit box with.
I recently played with this widget for my project, but it requires that the auto-complete suggestions must come from SQLite database.
Here's a video I shoot to show you the final output of our code.
Project Files
Our example project for today contains only 5 java files. Click the file names below to read its purpose and see the code inside.
- activity_main.xml
- MainActivity.java
- CustomAutoCompleteView.java
- DatabaseHandler.java
- CustomAutoCompleteTextChangedListener.java
- MyObject.java
Let's do the Code!
activity_main.xml - see how the AutoCompleteTextView widget was put in the XML layout. The tag looks like com.example.autocompletetextviewdb.CustomAutoCompleteView because it was referenced to our CustomAutoComputeView.java file.
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="" /> <com.example.autocompletetextviewdb.CustomAutoCompleteView android:id="@+id/myautocomplete" android:layout_width="fill_parent" android:layout_height="wrap_content" android:completionThreshold="1" > </com.example.autocompletetextviewdb.CustomAutoCompleteView> </LinearLayout>
MainActivity.java - this is where we initialize everything and insert sample data to the database.
package com.example.autocompletetextviewdb; import java.util.List; import android.os.Bundle; import android.app.Activity; import android.widget.ArrayAdapter; public class MainActivity extends Activity { /* * Change to type CustomAutoCompleteView instead of AutoCompleteTextView * since we are extending to customize the view and disable filter * The same with the XML view, type will be CustomAutoCompleteView */ CustomAutoCompleteView myAutoComplete; // adapter for auto-complete ArrayAdapter<String> myAdapter; // for database operations DatabaseHandler databaseH; // just to add some initial value String[] item = new String[] {"Please search..."}; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); try{ // instantiate database handler databaseH = new DatabaseHandler(MainActivity.this); // put sample data to database insertSampleData(); // autocompletetextview is in activity_main.xml myAutoComplete = (CustomAutoCompleteView) findViewById(R.id.myautocomplete); // add the listener so it will tries to suggest while the user types myAutoComplete.addTextChangedListener(new CustomAutoCompleteTextChangedListener(this)); // set our adapter myAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, item); myAutoComplete.setAdapter(myAdapter); } catch (NullPointerException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } public void insertSampleData(){ // CREATE databaseH.create( new MyObject("January") ); databaseH.create( new MyObject("February") ); databaseH.create( new MyObject("March") ); databaseH.create( new MyObject("April") ); databaseH.create( new MyObject("May") ); databaseH.create( new MyObject("June") ); databaseH.create( new MyObject("July") ); databaseH.create( new MyObject("August") ); databaseH.create( new MyObject("September") ); databaseH.create( new MyObject("October") ); databaseH.create( new MyObject("November") ); databaseH.create( new MyObject("December") ); databaseH.create( new MyObject("New Caledonia") ); databaseH.create( new MyObject("New Zealand") ); databaseH.create( new MyObject("Papua New Guinea") ); databaseH.create( new MyObject("COFFEE-1K") ); databaseH.create( new MyObject("coffee raw") ); databaseH.create( new MyObject("authentic COFFEE") ); databaseH.create( new MyObject("k12-coffee") ); databaseH.create( new MyObject("view coffee") ); databaseH.create( new MyObject("Indian-coffee-two") ); } // this function is used in CustomAutoCompleteTextChangedListener.java public String[] getItemsFromDb(String searchTerm){ // add items on the array dynamically List<MyObject> products = databaseH.read(searchTerm); int rowCount = products.size(); String[] item = new String[rowCount]; int x = 0; for (MyObject record : products) { item[x] = record.objectName; x++; } return item; } }
CustomAutoCompleteView.java - since we want the AutocompleteTextView to work with a database, we must customize by extending it.
package com.example.autocompletetextviewdb; import android.content.Context; import android.util.AttributeSet; import android.widget.AutoCompleteTextView; public class CustomAutoCompleteView extends AutoCompleteTextView { public CustomAutoCompleteView(Context context) { super(context); // TODO Auto-generated constructor stub } public CustomAutoCompleteView(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub } public CustomAutoCompleteView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); // TODO Auto-generated constructor stub } // this is how to disable AutoCompleteTextView filter @Override protected void performFiltering(final CharSequence text, final int keyCode) { String filterText = ""; super.performFiltering(filterText, keyCode); } /* * after a selection we have to capture the new value and append to the existing text */ @Override protected void replaceText(final CharSequence text) { super.replaceText(text); } }
DatabaseHandler.java - as the name suggests, this is where we can create the database, tables, manipulate and query the data.
package com.example.autocompletetextviewdb; import java.util.ArrayList; import java.util.List; import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; public class DatabaseHandler extends SQLiteOpenHelper { // for our logs public static final String TAG = "DatabaseHandler.java"; // database version private static final int DATABASE_VERSION = 4; // database name protected static final String DATABASE_NAME = "NinjaDatabase2"; // table details public String tableName = "locations"; public String fieldObjectId = "id"; public String fieldObjectName = "name"; // constructor public DatabaseHandler(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } // creating table @Override public void onCreate(SQLiteDatabase db) { String sql = ""; sql += "CREATE TABLE " + tableName; sql += " ( "; sql += fieldObjectId + " INTEGER PRIMARY KEY AUTOINCREMENT, "; sql += fieldObjectName + " TEXT "; sql += " ) "; db.execSQL(sql); } /* * When upgrading the database, it will drop the current table and recreate. */ @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { String sql = "DROP TABLE IF EXISTS " + tableName; db.execSQL(sql); onCreate(db); } /* * create new record * @param myObj contains details to be added as single row. */ public boolean create(MyObject myObj) { boolean createSuccessful = false; if(!checkIfExists(myObj.objectName)){ SQLiteDatabase db = this.getWritableDatabase(); ContentValues values = new ContentValues(); values.put(fieldObjectName, myObj.objectName); createSuccessful = db.insert(tableName, null, values) > 0; db.close(); if(createSuccessful){ Log.e(TAG, myObj.objectName + " created."); } } return createSuccessful; } // check if a record exists so it won't insert the next time you run this code public boolean checkIfExists(String objectName){ boolean recordExists = false; SQLiteDatabase db = this.getWritableDatabase(); Cursor cursor = db.rawQuery("SELECT " + fieldObjectId + " FROM " + tableName + " WHERE " + fieldObjectName + " = '" + objectName + "'", null); if(cursor!=null) { if(cursor.getCount()>0) { recordExists = true; } } cursor.close(); db.close(); return recordExists; } /* * Read records related to the search term */ public List<MyObject> read(String searchTerm) { List<MyObject> recordsList = new ArrayList<MyObject>(); // select query String sql = ""; sql += "SELECT * FROM " + tableName; sql += " WHERE " + fieldObjectName + " LIKE '%" + searchTerm + "%'"; sql += " ORDER BY " + fieldObjectId + " DESC"; sql += " LIMIT 0,5"; SQLiteDatabase db = this.getWritableDatabase(); // execute the query Cursor cursor = db.rawQuery(sql, null); // looping through all rows and adding to list if (cursor.moveToFirst()) { do { // int productId = Integer.parseInt(cursor.getString(cursor.getColumnIndex(fieldProductId))); String objectName = cursor.getString(cursor.getColumnIndex(fieldObjectName)); MyObject myObject = new MyObject(objectName); // add to list recordsList.add(myObject); } while (cursor.moveToNext()); } cursor.close(); db.close(); // return the list of records return recordsList; } }
CustomAutoCompleteTextChangedListener.java - this is where the program requeries the database each time a user types a character on the AutocompleteTextView.
package com.example.autocompletetextviewdb; import android.content.Context; import android.text.Editable; import android.text.TextWatcher; import android.util.Log; import android.widget.ArrayAdapter; public class CustomAutoCompleteTextChangedListener implements TextWatcher{ public static final String TAG = "CustomAutoCompleteTextChangedListener.java"; Context context; public CustomAutoCompleteTextChangedListener(Context context){ this.context = context; } @Override public void afterTextChanged(Editable s) { // TODO Auto-generated method stub } @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { // TODO Auto-generated method stub } @Override public void onTextChanged(CharSequence userInput, int start, int before, int count) { // if you want to see in the logcat what the user types Log.e(TAG, "User input: " + userInput); MainActivity mainActivity = ((MainActivity) context); // query the database based on the user input mainActivity.item = mainActivity.getItemsFromDb(userInput.toString()); // update the adapater mainActivity.myAdapter.notifyDataSetChanged(); mainActivity.myAdapter = new ArrayAdapter<String>(mainActivity, android.R.layout.simple_dropdown_item_1line, mainActivity.item); mainActivity.myAutoComplete.setAdapter(mainActivity.myAdapter); } }
MyObject.java - this is used for inserting sample data and other operations related to the database.
package com.example.autocompletetextviewdb; public class MyObject { public String objectName; // constructor for adding sample data public MyObject(String objectName){ this.objectName = objectName; } }
On the next post, we'll have this code with a custom ArrayAdapter so you can style the drop down that appears, see you!
Thanks for reading this Android AutocompleteTextView code example!
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