change the package name

app/src/main/java/com/simplemobiletools/draw/MainActivity.java

@@ -0,0 +1,53 @@
+package com.simplemobiletools.draw;
+
+import android.graphics.Color;
+import android.os.Bundle;
+import android.support.v7.app.AppCompatActivity;
+import android.view.View;
+
+import butterknife.Bind;
+import butterknife.ButterKnife;
+import butterknife.OnClick;
+import yuku.ambilwarna.AmbilWarnaDialog;
+
+public class MainActivity extends AppCompatActivity {
+    @Bind(R.id.my_canvas) MyCanvas myCanvas;
+    @Bind(R.id.color_picker) View colorPicker;
+    private int color;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+        ButterKnife.bind(this);
+
+        setColor(Color.BLACK);
+    }
+
+    @OnClick(R.id.undo)
+    public void undo() {
+        myCanvas.undo();
+    }
+
+    @OnClick(R.id.color_picker)
+    public void pickColor() {
+        AmbilWarnaDialog dialog = new AmbilWarnaDialog(this, color, new AmbilWarnaDialog.OnAmbilWarnaListener() {
+            @Override
+            public void onCancel(AmbilWarnaDialog dialog) {
+            }
+
+            @Override
+            public void onOk(AmbilWarnaDialog dialog, int pickedColor) {
+                setColor(pickedColor);
+            }
+        });
+
+        dialog.show();
+    }
+
+    private void setColor(int pickedColor) {
+        color = pickedColor;
+        colorPicker.setBackgroundColor(color);
+        myCanvas.setColor(color);
+    }
+}