Get two edittext values, retrieve output from database and show in textview in another activity

Question

I'm trying to display a bus number in a textview in another activity when a user enters their location and destination. I can't find where I am making mistakes:

DatabaseOpenHelper.java

public class DatabaseOpenHelper extends SQLiteAssetHelper {
    private static final String DATABASE_NAME = "CityBusManagementDatabase.db";
    private static final int DATABASE_VERSION = 1;

    public DatabaseOpenHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
}

DatabaseAccess.java

public class DatabaseAccess {
    private SQLiteOpenHelper openHelper;
    private SQLiteDatabase db;
    private static DatabaseAccess instance;
    Cursor c = null;

    //private constructor so that object creation from outside the class is avoided
    DatabaseAccess(Context context, Class<SearchResult> searchResultClass) {
        this.openHelper = new DatabaseOpenHelper(context);
    }

    //to return the single instance of database
    public static DatabaseAccess getInstance(Context context, Class<Dashboard> dashboardClass) {
        if (instance == null) {
            instance = new DatabaseAccess(context, SearchResult.class);
        }
        return instance;
    }

    //to open the database
    public void open() {
        this.db = openHelper.getWritableDatabase();
    }

    //closing the database connection
    public void close() {
        if (db != null) {
            this.db.close();
        }
    }

    public String getbus_number(String location, String destination) {
        c = db.rawQuery("Select bus_number from abuja where " + location + "= ? AND " + destination + " = ?", new String[]{location, destination});
        StringBuffer buffer = new StringBuffer();
        while (c.moveToNext()) {
            String bus_number = c.getString(0);
            buffer.append(""+bus_number);
        }
        return buffer.toString();
    }

    }
}

Dashboard.java

public class Dashboard extends AppCompatActivity {

    public EditText Location;
    public EditText GoToInput;
    public Button Search;

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

        Location = findViewById(R.id.location);
        GoToInput = findViewById(R.id.goToInput);

        Search = findViewById(R.id.search);
        Search.setOnClickListener(v -> {
            DatabaseAccess databaseAccess = new DatabaseAccess(getApplicationContext(), SearchResult.class);
            databaseAccess.open();
            String l = Location.getText().toString();
            String g = GoToInput.getText().toString();

        });
    }
}

SearchResult.java

public class SearchResult extends AppCompatActivity {

    public TextView BusNumberOutput;

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

        BusNumberOutput = findViewById(R.id.busNumberOutput);

        DatabaseAccess databaseAccess = DatabaseAccess.getInstance(getApplicationContext(), Dashboard.class);
        databaseAccess.open();

        String bus_number = databaseAccess.getbus_number(0, 1);
        // display the string into textView
       BusNumberOutput.setText(bus_number);
    }

}

activity_dashboard.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    android:background="#E5E5E5"
    tools:context=".Dashboard">

        <ImageView
            android:id="@+id/destination"
            android:layout_width="180dp"
            android:layout_height="230dp"
            android:layout_marginRight="15dp"
            android:layout_marginTop="105dp"
            android:layout_marginLeft="15dp"
            android:layout_marginBottom="15dp"
            android:scaleType="fitXY"
            app:srcCompat="@drawable/destinationpicture"/>

        <TextView
            android:id="@+id/welcome"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@+id/destination"
            android:text="Welcome!"
            android:textColor="@color/black"
            android:textSize="27sp"
            android:textStyle="bold"
            android:layout_marginTop="165dp"
            android:layout_marginBottom="15dp"
            android:layout_marginLeft="25dp"/>

    <TextView
        android:id="@+id/essay2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="215dp"
        android:layout_marginBottom="15dp"
        android:layout_toRightOf="@+id/destination"
        android:text="Let us help you find those bus numbers."
        android:textAlignment="center"
        android:textColor="@color/black"
        android:textSize="16sp"
        android:textStyle="normal" />

    <com.google.android.material.textfield.TextInputLayout
        android:id="@+id/location"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="32dp"
        android:layout_marginTop="450dp"
        android:layout_marginEnd="32dp"
        android:hint="Enter your location">

        <!--this is the actual edit text which takes the input-->
        <com.google.android.material.textfield.TextInputEditText
            android:id="@+id/location_text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/white"/>

    </com.google.android.material.textfield.TextInputLayout>

    <com.google.android.material.textfield.TextInputLayout
        android:id="@+id/goToInput"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="32dp"
        android:layout_marginTop="550dp"
        android:layout_marginEnd="32dp"
        android:hint="Enter your destination">

        <!--this is the actual edit text which takes the input-->
        <com.google.android.material.textfield.TextInputEditText
            android:id="@+id/goToInput_text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/white"/>

    </com.google.android.material.textfield.TextInputLayout>

    <Button
        android:id="@+id/search"
        android:layout_width="310dp"
        android:layout_height="90dp"
        android:layout_marginLeft="40dp"
        android:layout_marginTop="700dp"
        android:backgroundTint="#50C2C9"
        android:text="Search"
        android:textSize="20sp"/>

</RelativeLayout>

activity_search_result.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    android:background="#E5E5E5"
    tools:context=".SearchResult">

    <ImageView
        android:id="@+id/busStop"
        android:layout_width="355dp"
        android:layout_height="230dp"
        android:layout_marginRight="15dp"
        android:layout_marginTop="105dp"
        android:layout_marginLeft="25dp"
        android:layout_marginBottom="15dp"
        android:scaleType="fitXY"
        app:srcCompat="@drawable/busstoppicture" />

    <TextView
        android:id="@+id/busNumberIs"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Your Bus Number is:"
        android:textColor="@color/black"
        android:textSize="27sp"
        android:textStyle="bold"
        android:layout_marginTop="75dp"
        android:layout_marginBottom="15dp"
        android:layout_marginLeft="70dp"
        android:textAlignment="center"/>

    <TextView
        android:id="@+id/busNumberOutput"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text=""
        android:textColor="@color/black"
        android:textSize="27sp"
        android:textStyle="bold"
        android:layout_marginTop="75dp"
        android:layout_marginBottom="15dp"
        android:layout_marginLeft="200dp"
        android:textAlignment="center"/>

    <TextView
        android:id="@+id/thanks"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="40dp"
        android:layout_marginLeft="65dp"
        android:text="Thank you for using CBMA!"
        android:textAlignment="center"
        android:textColor="@color/black"
        android:textSize="21sp"
        android:textStyle="normal" />

    <Button
        android:id="@+id/searchAgain"
        android:layout_width="310dp"
        android:layout_height="90dp"
        android:layout_marginLeft="40dp"
        android:layout_marginTop="20dp"
        android:backgroundTint="#50C2C9"
        android:text="Search Again"
        android:textSize="20sp"/>

</LinearLayout>

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. — Community, Oct 31 '22 at 06:23

MikeT · Answer 1 · 2022-10-31T07:45:29.590

I can't find where I am making mistakes:

You need to learn how to debug. However, here's some pointers.

DatabaseOpenHelper

OK as it is

DatabaeAccess (see comments):-

public class DatabaseAccess {
   private SQLiteOpenHelper openHelper;
   private SQLiteDatabase db;
   private static DatabaseAccess instance;
   Cursor c = null;

   //private constructor so that object creation from outside the class is avoided
   /*<<<<<<<<<< Database should be distinct from UI so no need for UI classes being passed to constructors >>>>>>>>>>*/
   DatabaseAccess(Context context/*, Class<SearchResult> searchResultClass*/) {
      this.openHelper = new DatabaseOpenHelper(context);
   }

   //to return the single instance of database
   public static DatabaseAccess getInstance(Context context/*<<<<<<<<<<, Class<Dashboard> dashboardClass>>>>>>>>>>*/) {
      if (instance == null) {
         instance = new DatabaseAccess(context/*<<<<<<<<<<, SearchResult.class*>>>>>>>>>>*/);
      }
      return instance;
   }

   //to open the database
   public void open() {
      this.db = openHelper.getWritableDatabase();
   }

   //closing the database connection
   public void close() {
      if (db != null) {
         this.db.close();
      }
   }

   public String getbus_number(String location, String destination) {
      /*<<<<<<<<<< column names should be specifically location and destination not variables location and destination resolved >>>>>>>>>>*/
      c = db.rawQuery("Select bus_number from abuja where location =? AND destination =?", new String[]{location, destination});
      StringBuffer buffer = new StringBuffer();
      while (c.moveToNext()) {
         String bus_number = c.getString(0);
         buffer.append(""+bus_number);
      }
      c.close(); /* SHOULD ALWAYS CLOSE CURSOR WHEN DONE WITH IT */
      return buffer.toString();
   }
}

Dashboard (see comments)

public class Dashboard extends AppCompatActivity {

    public EditText Location;
    public EditText GoToInput;
    public Button Search;

    public static final String INTENT_EXTRA_DASHBOARD_LOCATION = "IEDASHBOARDLOCATION"; /*<<<<<<<<<< ADDED >>>>>>>>>>*/
    public static final String INTENT_EXTRA_DASHBOARD_DESTINATION = "IEDASHBOARDDESTINATION"; /*<<<<<<<<<< ADDED >>>>>>>>>>*/

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

        //Location = findViewById(R.id.location); /*<<<<<<<<<< WRONG ERROR SO COMMENTED OUT >>>>>>>>>>*/
        Location = findViewById(R.id.location_text); /*<<<<<<<<<< IMPORTANT CHANGED  >>>>>>>>>>*/
        //GoToInput = findViewById(R.id.goToInput); /*<<<<<<<<<< WRONG ERROR SO COMMENTED OUT >>>>>>>>>>*/
        GoToInput = findViewById(R.id.goToInput_text); /*<<<<<<<<<< IMPORTANT CHANGED  >>>>>>>>>>*/

        Search = findViewById(R.id.search);
        Search.setOnClickListener(v -> {
            /*<<<<<<<<<< NO need to access the database here so commented out >>>>>>>>>>*/
            //DatabaseAccess databaseAccess = new DatabaseAccess(getApplicationContext()/*, SearchResult.class*/);
            //databaseAccess.open();
            //String l = Location.getText().toString();
            //String g = GoToInput.getText().toString();
            /*<<<<<<<<<< WHAT YOU NEED TO DO IS >>>>>>>>>>*/
            /* PREPARE TO INVOKE THE SEARCHRESULTS PASSINg THE VALUES TO SEARCH RESULTS */
            Intent intent = new Intent(getApplicationContext(),SearchResult.class); /* prepare an intent to start the searchresult activity */
            intent.putExtra(INTENT_EXTRA_DASHBOARD_LOCATION,Location.getText().toString()); /* store the location input in an intent extra */
            intent.putExtra(INTENT_EXTRA_DASHBOARD_DESTINATION,GoToInput.getText().toString()); /* store the destination input in an intent extra */
            startActivity(intent); /* Start the SEARCHRESULT Activity  that can then get the extras from the intent*/
        });
    }
}

SearchResult (see comments)

public class SearchResult extends AppCompatActivity {

    public TextView BusNumberOutput;

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

        BusNumberOutput = findViewById(R.id.busNumberOutput);

        DatabaseAccess databaseAccess = DatabaseAccess.getInstance(getApplicationContext()/*, Dashboard.class*/);
        databaseAccess.open();

        /*<<<<<<<<<< CHANGED TO USE location and destination from the dashboard activity */
        String bus_number = databaseAccess.getbus_number(
                this.getIntent().getStringExtra(Dashboard.INTENT_EXTRA_DASHBOARD_LOCATION),
                this.getIntent().getStringExtra(Dashboard.INTENT_EXTRA_DASHBOARD_DESTINATION)
        );
        // display the string into textView
        BusNumberOutput.setText(bus_number);
    }
}

Demo

So using a database that has the abuja table as per :-

And copying the database into the assets/databases folder of the project (after creating the folders) as per:-

as you can see the project contains the respective code
- note the images were removed from the layout for the sake of not having to work on them.

In addition to the provided code MainActivity (Button defined in the layout) was:-

public class MainActivity extends AppCompatActivity {

    Button dashboard_button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        dashboard_button = this.findViewById(R.id.dashboard_button);
        dashboard_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(getApplicationContext(),Dashboard.class);
                startActivity(intent);
            }
        });
    }
}

So when run then :-

Clicking the DASHBOARD button :-

Entering location 1 and destination 2 and clicking SEARCH :-

i.e. BUS012 as expected.
- that is BUS0 is for all busses the next digit reflects the location, the last digit represents the destination (see the database above).
The display will be lacking the images as these have been removed.

Additional

In response to

but what if the location and destination are in text form not in integer form

As per the comment no issue at all.

As proof I added the following to MainActiviy:-

DatabaseAccess.getInstance(this).insert("BUSLONDON-NEWYORK","London","New York");

Along with the following additional method in DatabaseAccess :-

public long insert(String bus_number, String location, String destination) {
    ContentValues cv = new ContentValues();
    cv.put("bus_number",bus_number);
    cv.put("location",location);
    cv.put("destination",destination);
    return instance.openHelper.getWritableDatabase().insert("abuja",null,cv);
}

thus a new row with the bus name as BUSLONDON-NEWYORK, the location as London and the destination as New York.

Without any other changes the the App was run and London input as the location and New York as the destination resulting in:-

Thank you very much, I am really grateful. I was so confused. I am so sorry for not adding it before but what if the location and destination are in text form not in integer form like your own? Do I also need the TextDB.db? — Ifedolapo Ajayi, Oct 31 '22 at 07:13
@IfedolapoAjayi text/integer doesn't matter as long as the input data matches. The data obtained from the edit text is a string, is is the getStringExtra when retrieving from the extra also ? in the SQL is bound as a String. I used number values to reflect your code as per `String bus_number = databaseAccess.getbus_number(0, 1);`. — MikeT, Oct 31 '22 at 07:27
@IfedolapoAjayi Oh **Text.db** is actually exactly the same as bar the file name as CityBusManagementDatabase.db. I created the database using a tool and that's just the name of the database I used. Copied the file into the asset and then just copied and pasted it as CityBusManagementDatabase.db. — MikeT, Oct 31 '22 at 07:38
@IfedolapoAjayi updated the answer showing text location and destination being used (the code being changed JUST to insert a row with text location and destination). — MikeT, Oct 31 '22 at 07:46

Get two edittext values, retrieve output from database and show in textview in another activity

1 Answers1