How can I move an image based on a user's touch?

Question

I am trying to get an image to move, either to the Left Or Right, when the user touches either the Left Or Right of their device's screen. I have the following code....I have run the Emulator, in Android Studio, and when I click on the Right or Left sides of the Emulator's Screen....nothing happens. What is wrong with this code? All answers are welcome! I have entered the following code in the Activity that has the image I want to move:

public class GameScreen1 extends AppCompatActivity implements View.OnTouchListener{


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_game_screen1);


    ImageView circle1 = (ImageView) findViewById(R.id.circle1);

}

@Override
public boolean onTouch(View v, MotionEvent event) {
    switch (v.getId()) {
        case R.id.circle1:
            if (event.getAction() == MotionEvent.ACTION_DOWN) {
                //WHAT CODE SHOULD I PUT INSTEAD OF THE FLOAT X AND X++
                int ScreenWidth = getResources().getDisplayMetrics().widthPixels;
                float Xtouch = event.getRawX();
                int sign = Xtouch > 0.5*ScreenWidth ? 1 : -1;
                float XToMove = 50;
                int durationMs = 50;
                v.animate().translationXBy(sign*XToMove).setDuration(durationMs);
            }
            break;
    }
    return false;
}

}

Use `return true;` instead of breaking the case. – Jay Jun 14 '18 at 13:32 — Jay, Jun 14 '18 at 13:32

score 1 · Accepted Answer · answered Jun 14 '18 at 13:52

Add ID to your root layout in the activity and add TouchListener on it.

Here's an example:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:id="@+id/cl_root"
    android:layout_height="match_parent"
    tools:context=".MainActivity">


</android.support.constraint.ConstraintLayout>

And This is the code of your activity:

public class MainActivity extends AppCompatActivity {

    ConstraintLayout layout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        layout = findViewById(R.id.cl_root);
        layout.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                int screenWidth = getResources().getDisplayMetrics().widthPixels;
                int x = (int)event.getX();
                if ( x >= ( screenWidth/2) ) {
                    //Right touch
                }else {
                    //Left touch
                }
                return false;
            }
        });

    }
}

How can I move an image based on a user's touch?

1 Answers1