Cannot resolves Symbol

Question

I’m following the tutorial (Android Studio 2.3 Development Essentials) but this giving this error

cannot resolve Symbol

in that part of the code

ConstraintLayout myLayout =
            (ConstraintLayout)findViewById(R.id.activity_motion_event);

this is the action_motion_event.xml file-

<?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="aprendendo.com.motionevent.MotionEventActivity">


    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="@string/touch_one_status"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="32dp"
        android:text="@string/touch_two_status"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView1" />
</android.support.constraint.ConstraintLayout>

this is the code of Motioneventactivity

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


    ConstraintLayout myLayout =
            (ConstraintLayout)findViewById(R.id.activity_motion_event);

    myLayout.setOnTouchListener(
            new ConstraintLayout.OnTouchListener(){
                public boolean onTouch(View v,
                                       MotionEvent m){
                    handleTouch(m);
                    return true;
                }
            }
    );

}
void handleTouch(MotionEvent m){
    TextView textView1 = (TextView)findViewById(R.id.textView1);
    TextView textView2 = (TextView)findViewById(R.id.textView2);

    int pointerCount = m.getPointerCount();

    for (int i = 0; i < pointerCount; i++){
        int x = (int) m.getX(i);
        int y = (int) m.getY(i);
        int id = m.getPointerId(i);
        int action = m.getActionMasked();
        int actionIndex = m.getActionIndex();
        String actionString;

        switch (action){
            case MotionEvent.ACTION_DOWN:
                actionString = "DOWN";
                break;
            case MotionEvent.ACTION_UP:
                actionString = "UP";
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                actionString = "PNTR DOWN";
                break;
            case MotionEvent.ACTION_POINTER_UP:
                actionString = "PNTR UP";
                break;
            case MotionEvent.ACTION_MOVE:
                actionString = "MOVE";
                break;
            default:
                actionString = "";
        }
        String touchStatus = "Action: " + actionString + " Index: " +
                actionIndex + " ID: " + id + " X: " + x + " Y: " + y;

        if (id == 0)
            textView1.setText(touchStatus);
        else
            textView2.setText(touchStatus);
    }
}

}

Answer 1

You did not set the parameter "id" with the value "activity_motion_event" in the XML Constraintlayout tag.