Android Studio (Java)
The SimplePaint app (full code given below) allows users to draw pictures by pressing the screen in the app.
The existing SimplePaint app allows users to draw using "circles" using the "SimpleDrawingView.java (using circles)" code given below. Add a button at the top of the app to allow users to toggle between drawing:
(a) using circle
(b) using path (path code is given below)
activity_main.xml
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
/>
MainActivity.java
package com.example.simplepaint;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
SimpleDrawingView.java (using circles)
package com.example.simplepaint;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import java.util.ArrayList;
import java.util.List;
public class SimpleDrawingView extends View {
// setup initial color
private final int paintColor = Color.BLACK;
// defines paint and canvas
private Paint drawPaint;
// Store circles to draw each time the user touches down
private List circlePoints;
public SimpleDrawingView(Context context, AttributeSet attrs) {
super(context, attrs);
setupPaint(); // same as before
circlePoints = new ArrayList();
}
// Draw each circle onto the view
@Override
protected void onDraw(Canvas canvas) {
for (Point p : circlePoints) {
canvas.drawCircle(p.x, p.y, 5, drawPaint);
}
}
// Append new circle each time user presses on screen
@Override
public boolean onTouchEvent(MotionEvent event) {
float touchX = event.getX();
float touchY = event.getY();
circlePoints.add(new Point(Math.round(touchX), Math.round(touchY)));
// indicate view should be redrawn
postInvalidate();
return true;
}
private void setupPaint() {
drawPaint = new Paint();
drawPaint.setColor(paintColor);
.
Android Studio (Java)The SimplePaint app (full code given below).docx
1. Android Studio (Java)
The SimplePaint app (full code given below) allows users to
draw pictures by pressing the screen in the app.
The existing SimplePaint app allows users to draw using
"circles" using the "SimpleDrawingView.java (using circles)"
code given below. Add a button at the top of the app to allow
users to toggle between drawing:
(a) using circle
(b) using path (path code is given below)
activity_main.xml
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
5. // setup initial color
private final int paintColor = Color.BLACK;
// defines paint and canvas
private Paint drawPaint;
// Store circles to draw each time the user touches down
private List circlePoints;
public SimpleDrawingView(Context context, AttributeSet
attrs) {
super(context, attrs);
setupPaint(); // same as before
circlePoints = new ArrayList();
}
6. // Draw each circle onto the view
@Override
protected void onDraw(Canvas canvas) {
for (Point p : circlePoints) {
canvas.drawCircle(p.x, p.y, 5, drawPaint);
}
}
// Append new circle each time user presses on screen
@Override
public boolean onTouchEvent(MotionEvent event) {
float touchX = event.getX();
7. float touchY = event.getY();
circlePoints.add(new Point(Math.round(touchX),
Math.round(touchY)));
// indicate view should be redrawn
postInvalidate();
return true;
}
private void setupPaint() {
drawPaint = new Paint();
drawPaint.setColor(paintColor);
drawPaint.setAntiAlias(true);
drawPaint.setStrokeWidth(5);
9. import android.graphics.Path;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class SimpleDrawingView extends View {
// setup initial color
private final int paintColor = Color.BLACK;
// defines paint and canvas
private Paint drawPaint;
// stores next circle
private Path path = new Path();
10. public SimpleDrawingView(Context context, AttributeSet
attrs) {
super(context, attrs);
setFocusable(true);
setFocusableInTouchMode(true);
setupPaint();
}
private void setupPaint() {
// Setup paint with color and stroke styles
drawPaint = new Paint();
drawPaint.setColor(paintColor);
drawPaint.setAntiAlias(true);
