Adding an Eraser and Starting a New Drawing

app/src/main/java/com/dragosholban/androiddrawing/DrawingView.java

@@ -73,4 +73,11 @@ public void setCurrentColor(int color) {
    public void setCurrentWidth(int width) {
        currentWidth = (width + 1) * 2;
    }

    public void erase() {
        paths.clear();
        colors.clear();
        widths.clear();
        invalidate();
    }
}

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

@@ -1,6 +1,8 @@
package com.dragosholban.androiddrawing;

import android.content.DialogInterface;
import android.graphics.drawable.ColorDrawable;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
@@ -41,5 +43,28 @@ public void onStopTrackingTouch(SeekBar seekBar) {
    public void setColor(View view) {
        ColorDrawable buttonColor = (ColorDrawable) view.getBackground();
        drawingView.setCurrentColor(buttonColor.getColor());
        if (view.getTag() != null && view.getTag().equals("eraser")) {
            drawingView.setCurrentWidth(seekBar.getProgress() * 4);
        } else {
            drawingView.setCurrentWidth(seekBar.getProgress());
        }
    }

    public void deleteDrawing(View view) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setMessage("Are you sure you want to erase everything?")
                .setTitle("Delete Drawing")
                .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        drawingView.erase();
                    }
                })
                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {

                    }
                });
        AlertDialog dialog = builder.create();
        dialog.show();
    }
}

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

@@ -62,6 +62,21 @@
            android:layout_margin="1dp"
            android:background="#000000"
            android:onClick="setColor"/>
        <View
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:layout_margin="1dp"
            android:background="#FFFFFF"
            android:onClick="setColor"
            android:tag="eraser"/>
        <Button
            android:id="@+id/button"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@android:drawable/ic_menu_delete"
            android:onClick="deleteDrawing" />
    </LinearLayout>
    <SeekBar
        android:id="@+id/seekBar"