Changing the Color

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

@@ -15,6 +15,8 @@
public class DrawingView extends View {

    private ArrayList<Path> paths = new ArrayList<>();
    private ArrayList<Integer> colors = new ArrayList<>();
    private int currentColor = 0xFF000000;

    public DrawingView(Context context) {
        super(context);
@@ -35,6 +37,7 @@ public DrawingView(Context context, @Nullable AttributeSet attrs, int defStyleAt

    public void addPath(Path path) {
        paths.add(path);
        colors.add(currentColor);
    }

    public Path getLastPath() {
@@ -49,12 +52,18 @@ public Path getLastPath() {
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int i = 0;
        for (Path path : paths) {
            Paint paint = new Paint();
            paint.setColor(0X80000000);
            paint.setColor(colors.get(i));
            paint.setStyle(Paint.Style.STROKE);
            paint.setStrokeWidth(3f);
            canvas.drawPath(path, paint);
            i++;
        }
    }

    public void setCurrentColor(int color) {
        currentColor = color;
    }
}

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

@@ -1,7 +1,9 @@
package com.dragosholban.androiddrawing;

import android.graphics.drawable.ColorDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

@@ -15,4 +17,9 @@ protected void onCreate(Bundle savedInstanceState) {
        drawingView = findViewById(R.id.canvas);
        drawingView.setOnTouchListener(new TouchListener());
    }

    public void setColor(View view) {
        ColorDrawable buttonColor = (ColorDrawable) view.getBackground();
        drawingView.setCurrentColor(buttonColor.getColor());
    }
}

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

@@ -39,24 +39,28 @@
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:layout_margin="1dp"
            android:background="#FF0000"/>
            android:background="#FF0000"
            android:onClick="setColor"/>
        <View
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:layout_margin="1dp"
            android:background="#00FF00"/>
            android:background="#00FF00"
            android:onClick="setColor"/>
        <View
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:layout_margin="1dp"
            android:background="#0000FF"/>
            android:background="#0000FF"
            android:onClick="setColor"/>
        <View
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:layout_margin="1dp"
            android:background="#000000"/>
            android:background="#000000"
            android:onClick="setColor"/>
    </LinearLayout>
</android.support.constraint.ConstraintLayout>