Adding an Eraser and Starting a New Drawing

Author: dragosholban

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"