Drag the Image Pieces Around

app/src/main/java/dragosholban/com/androidpuzzlegame/MainActivity.java

@@ -8,6 +8,7 @@
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.RelativeLayout;

import java.util.ArrayList;

@@ -21,7 +22,7 @@ protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final ConstraintLayout layout = findViewById(R.id.layout);
        final RelativeLayout layout = findViewById(R.id.layout);
        ImageView imageView = findViewById(R.id.imageView);

        // run image related code after the view was laid out
@@ -30,9 +31,11 @@ protected void onCreate(Bundle savedInstanceState) {
            @Override
            public void run() {
                pieces = splitImage();
                TouchListener touchListener = new TouchListener();
                for(Bitmap piece : pieces) {
                    ImageView iv = new ImageView(getApplicationContext());
                    iv.setImageBitmap(piece);
                    iv.setOnTouchListener(touchListener);
                    layout.addView(iv);
                }
            }

app/src/main/java/dragosholban/com/androidpuzzlegame/TouchListener.java

@@ -0,0 +1,30 @@
package dragosholban.com.androidpuzzlegame;

import android.view.MotionEvent;
import android.view.View;
import android.widget.RelativeLayout;

public class TouchListener implements View.OnTouchListener {
    private float xDelta;
    private float yDelta;

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {
        float x = motionEvent.getRawX();
        float y = motionEvent.getRawY();
        RelativeLayout.LayoutParams lParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
        switch (motionEvent.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                xDelta = x - lParams.leftMargin;
                yDelta = y - lParams.topMargin;
                break;
            case MotionEvent.ACTION_MOVE:
                lParams.leftMargin = (int) (x - xDelta);
                lParams.topMargin = (int) (y - yDelta);
                view.setLayoutParams(lParams);
                break;
        }

        return true;
    }
}

app/src/main/res/layout/activity_main.xml

@@ -4,8 +4,7 @@
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="dragosholban.com.androidpuzzlegame.MainActivity"
    android:id="@+id/layout">
    tools:context="dragosholban.com.androidpuzzlegame.MainActivity">

    <ImageView
        android:id="@+id/imageView"
@@ -23,4 +22,14 @@
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/photo" />

    <RelativeLayout
        android:id="@+id/layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent">
    </RelativeLayout>
</android.support.constraint.ConstraintLayout>