AutoPopulate EditText in Android Studio from SQLite Database

Question

I am attempting to autocomplete the EditText in my application, however not through means of typing but from one entry to another. What I mean is that when the user enters "Student ID", the "First Name" and "Last Name" fields will be auto-populated with the corresponding data from the SQLite database if it is present.

My current XML File is as follows:

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#d5ebfd"
    android:orientation="vertical">


    <TextView
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:text="Student Grade Management System"
        android:textSize="20dp"
        android:textColor="#ff0000"
        android:gravity="center"
        android:fontFamily="serif"
        android:textStyle="bold"/>

    <EditText
        android:id="@+id/studentID"
        android:layout_width="match_parent"
        android:paddingTop="20dp"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="number"
        android:hint="Enter Student ID (Used for Updating/Deleting): " />
    <requestFocus />

    <EditText
        android:id="@+id/firstName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="Enter First Name: " />

    <EditText
        android:id="@+id/lastName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="Enter Last Name: " />

    <EditText
        android:id="@+id/classID"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="number"
        android:hint="Enter Class ID: " />

    <EditText
        android:id="@+id/className"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="Enter Class Name: " />

    <EditText
        android:id="@+id/gradePoint"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="number"
        android:hint="Enter Grade Point (0-100): " />

    <EditText
        android:id="@+id/letterGrade"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="Enter Letter Grade: " />


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp" >

        <Button
            android:id="@+id/addbtn"
            android:layout_width="200dp"
            android:layout_height="50dp"
            android:text="Add" />

        <Button
            android:id="@+id/deletebtn"
            android:layout_width="200dp"
            android:layout_height="50dp"
            android:text="Delete" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp" >

        <Button
            android:id="@+id/viewall"
            android:layout_width="200dp"
            android:layout_height="50dp"
            android:text="View" />

        <Button
            android:id="@+id/modifystudent"
            android:layout_width="200dp"
            android:layout_height="50dp"
            android:text="Update Student Info" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp" >

        <Button
            android:id="@+id/modifyclass"
            android:layout_width="200dp"
            android:layout_height="50dp"
            android:text="Update Class Info" />

        <Button
            android:id="@+id/modifygrade"
            android:layout_width="200dp"
            android:layout_height="50dp"
            android:text="Update Grade Info" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0.74" >

    </LinearLayout>

</LinearLayout>

The Main Activity Looks like this:

public class MainActivity extends Activity {
    EditText fname,lname,classid,classname,pointgrade,lettergrade,studentid;
    Button add,view,viewall,delete,modifystudent, modifyclass, modifygrade;
    SQLiteDatabase db;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        studentid=(EditText)findViewById(R.id.studentID);
        fname=(EditText)findViewById(R.id.firstName);
        lname=(EditText)findViewById(R.id.lastName);
        classid=(EditText)findViewById(R.id.classID);
        classname=(EditText)findViewById(R.id.className);
        pointgrade=(EditText)findViewById(R.id.gradePoint);
        lettergrade=(EditText)findViewById(R.id.letterGrade);
        add=(Button)findViewById(R.id.addbtn);
        viewall=(Button)findViewById(R.id.viewall);
        delete=(Button)findViewById(R.id.deletebtn);
        modifystudent=(Button)findViewById(R.id.modifystudent);
        modifyclass=(Button)findViewById(R.id.modifyclass);
        modifygrade=(Button)findViewById(R.id.modifygrade);

        db=openOrCreateDatabase("STUDENTGRADES", Context.MODE_PRIVATE, null);
        db.execSQL("CREATE TABLE IF NOT EXISTS CUSTOMER_TABLE(studentid VARCHAR, fname VARCHAR, lname VARCHAR, classid VARCHAR, classname VARCHAR, pointgrade INTEGER, lettergrade VARCHAR);");


        add.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if(fname.getText().toString().trim().length()==0||
                        lname.getText().toString().trim().length()==0 || studentid.getText().toString().trim().length()==0)
                {
                    showMessage("Error", "Please enter First & Last Name and Student ID");
                    return;
                }
                db.execSQL("INSERT INTO CUSTOMER_TABLE VALUES('"+studentid.getText()+"','"+fname.getText()+"','"+lname.getText()+"','"+classid.getText()+"','"+classname.getText()+
                        "','"+pointgrade.getText()+"','"+lettergrade.getText()+"');");
                showMessage("Success", "Record added successfully");
                clearText();
            }
        });
        delete.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if(studentid.getText().toString().trim().length()==0 || classid.getText().toString().trim().length()==0)
                {
                    showMessage("Error", "Please enter Student and Class ID ");
                    return;
                }
                Cursor c=db.rawQuery("SELECT * FROM CUSTOMER_TABLE WHERE studentid='"+studentid.getText()+"' AND classid='"+classid.getText()+"'", null);
                if(c.moveToFirst())
                {
                    db.execSQL("DELETE FROM CUSTOMER_TABLE WHERE studentid='"+studentid.getText()+"' AND classid='"+classid.getText()+"'");
                    showMessage("Success", "Record Deleted");
                }
                else
                {
                    showMessage("Error", "Invalid First and Last Name or Student ID");
                }
                clearText();
            }
        });
        modifystudent.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if(fname.getText().toString().trim().length()==0 || lname.getText().toString().trim().length()==0 || studentid.getText().toString().trim().length()==0)
                {
                    showMessage("Error", "Please enter Student First & Last Name and ID to update student info. \n\nAll other Field Entries will be ignored");
                    return;
                }
                Cursor c=db.rawQuery("SELECT * FROM CUSTOMER_TABLE WHERE studentid='"+studentid.getText()+"'", null);
                if(c.moveToFirst())
                {
                    db.execSQL("UPDATE CUSTOMER_TABLE SET fname='"+fname.getText()+"',lname='"+lname.getText()+"' WHERE studentid='"+studentid.getText()+"'");
                    showMessage("Success", "Name Record Modified");
                }
                else
                {
                    showMessage("Error", "Invalid First and Last name or Student ID");
                }
                clearText();
            }
        });

        modifyclass.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if(studentid.getText().toString().trim().length()==0 || classid.getText().toString().trim().length()==0 || classname.getText().toString().trim().length()==0)
                {
                    showMessage("Error", "Please enter Student & Class ID to update class. \n\nAll other Field Entries will be ignored");
                    return;
                }
                Cursor c=db.rawQuery("SELECT * FROM CUSTOMER_TABLE WHERE classid='"+classid.getText()+"'", null);
                if(c.moveToFirst())
                {
                    db.execSQL("UPDATE CUSTOMER_TABLE SET classid='"+classid.getText()+"',classname='"+classname.getText()+"' WHERE studentid='"+studentid.getText()+"' AND classid='"+classid.getText()+"'");
                    showMessage("Success", "Class Record Modified");
                }
                else
                {
                    showMessage("Error", "Invalid First and Last name or Class ID");
                }
                clearText();
            }
        });

        modifygrade.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if(studentid.getText().toString().trim().length()==0 || classid.getText().toString().trim().length()==0 || classname.getText().toString().trim().length()==0)
                {
                    showMessage("Error", "Please enter Student & Class ID to update grades. \n\nAll other Field Entries will be ignored");
                    return;
                }
                Cursor c=db.rawQuery("SELECT * FROM CUSTOMER_TABLE WHERE classid='"+classid.getText()+"' AND studentid='"+studentid.getText()+"'", null);
                if(c.moveToFirst())
                {
                    db.execSQL("UPDATE CUSTOMER_TABLE SET pointgrade='"+pointgrade.getText()+"',lettergrade='"+lettergrade.getText()+"' WHERE classid='"+classid.getText()+"' AND studentid='"+studentid.getText()+"'");
                    showMessage("Success", "Grade Record Modified");
                }
                else
                {
                    showMessage("Error", "Invalid First and Last name or Class ID");
                }
                clearText();
            }
        });

        viewall.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Cursor c=db.rawQuery("SELECT * FROM CUSTOMER_TABLE", null);
                if(c.getCount()==0)
                {
                    showMessage("Error", "No records found");
                    return;
                }
                StringBuffer buffer=new StringBuffer();
                while(c.moveToNext())
                {
                    buffer.append("ID: "+c.getString(0)+"\n");
                    buffer.append("Student Name: "+c.getString(1)+" " +c.getString(2)+"\n");
                    buffer.append("Class ID: "+c.getString(3)+"\n");
                    buffer.append("Class Name: "+c.getString(4)+"\n");
                    buffer.append("Points: "+c.getString(5)+"\n");
                    buffer.append("Grade: "+c.getString(6)+"\n\n");
                }
                showMessage("Student Report", buffer.toString());
            }
        });


    }
    public void showMessage(String title,String message)
    {
        Builder builder=new Builder(this);
        builder.setCancelable(true);
        builder.setTitle(title);
        builder.setMessage(message);
        builder.show();
    }
    public void clearText()
    {
        studentid.setText("");
        fname.setText("");
        lname.setText("");
        classid.setText("");
        classname.setText("");
        pointgrade.setText("");
        lettergrade.setText("");
        studentid.requestFocus();

    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

Any direct assistance is greatly appreciated, Thank you!

Answer 1

This can be completed with a Text Change Listener/Text Watcher. For the above request this can be implemented as follows, and will autofill with data from the SQLite Database

studentid.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                Cursor c = db.rawQuery("SELECT * FROM " + STUDENT_TABLE + " WHERE studentid='" + s.toString() + "'", null);
                if (c.moveToFirst()) {
                    fname.setText(c.getString(1));
                    lname.setText(c.getString(2));
                } else {
                    fname.setText("");
                    lname.setText("");
                }
                c.close();
            }
        });