Catch the Ball - Android Studio Game Tutorial - Bonus #3

MainActivity.java

package com.codingwithsara.moveimage;

import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.ImageView;

import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends AppCompatActivity implements View.OnTouchListener {

    private ImageView box;
    private FrameLayout frame;
    private Drawable imageBoxRight, imageBoxLeft;
    private float boxX, boxY;
    private boolean action_up, action_down, action_left, action_right;

    private Timer timer = new Timer();
    private Handler handler = new Handler();

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

        box = findViewById(R.id.box);
        frame = findViewById(R.id.frame);
        imageBoxLeft = getResources().getDrawable(R.drawable.box_left);
        imageBoxRight = getResources().getDrawable(R.drawable.box_right);

        findViewById(R.id.upBtn).setOnTouchListener(this);
        findViewById(R.id.downBtn).setOnTouchListener(this);
        findViewById(R.id.leftBtn).setOnTouchListener(this);
        findViewById(R.id.rightBtn).setOnTouchListener(this);

        // Start the timer
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                handler.post(new Runnable() {
                    @Override
                    public void run() {
                        changePos();
                    }
                });
            }
        }, 0, 20);
    }

    public void changePos() {
        boxX = box.getX();
        boxY = box.getY();

        // Up
        if (action_up) boxY -= 20;

        // Down
        if (action_down) boxY += 20;

        // Left
        if (action_left) {
            boxX -= 20;
            box.setImageDrawable(imageBoxLeft);
        }

        // Right
        if (action_right) {
            boxX += 20;
            box.setImageDrawable(imageBoxRight);
        }

        // Vertical Move
        if (boxY < 0) boxY = 0;
        if (boxY > frame.getHeight() - box.getHeight()) boxY = frame.getHeight() - box.getHeight();

        // Horizontal Move
        if (boxX < 0) {
            boxX = 0;
            box.setImageDrawable(imageBoxRight);
        }
        if (boxX > frame.getWidth() - box.getWidth()) {
            boxX = frame.getWidth() - box.getWidth();
            box.setImageDrawable(imageBoxLeft);
        }

        box.setX(boxX);
        box.setY(boxY);
    }

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
            switch (view.getId()) {
                case R.id.upBtn:
                    action_up = true;
                    break;
                case R.id.downBtn:
                    action_down = true;
                    break;
                case R.id.leftBtn:
                    action_left = true;
                    break;
                case R.id.rightBtn:
                    action_right = true;
                    break;
            }
        } else {
            action_up = false;
            action_down = false;
            action_left = false;
            action_right = false;
        }
        return true;
    }
}