Lab7d
Animation, movement and buttons (again)

Create Lab7d1, remove init and paint methods

Paste this in the applet showing an animated circle.

Notice in this example, repaint and delay are not inside the nested if.. elses - instead of giving each section its own repaint and delay I used one set at the bottom - It does not compile yet.

Moving horizontally in a wrap motion

1. Add this to the global variable section      int k = 10;

2. Add this after the delay in paint - familiar wrap code

Do you have any idea why i went circle3, circle2, circle1 ?

Adding Buttons to change directions

Now we are are going to add Buttons from Unit 6 Lab6e - since there is room at the top, we will go with the default FlowLayout

1. add with the import section          import java.awt.event.*;

2. add after the word applet - at the top      implements ActionListener
    ( it will not compile until step 5)

3. add with the global variables

4. add to the init method after the background color is set

5. add this method BEFORE the paint method - you can compile and see the buttons

6. This step is tricky - To make the buttons work, we will need another if ... else inside paint around the if.. else we already have

Try it - it should now work - call me if you are having problems --you should see this 

Check list of what you should be familiar with

• Move an object across the screen horizontally or vertically in a warpping or a bouncing style(Lab7a)
• Add buttons on the top (flow Layout) or on the bottom, top, right or left sides with a panel and a Border Layout(Lab7b)
• Use the buttons to start and stop (Lab7b), use buttons to change directions (Lab7d)
• Use nested if..else to create the impression of animation( Lab7c) and (Lab7d)

1. Copy your Java file from Lab7d1. Close the workspace

2. Create applet Lab7d2. Paste over the entire Java file, change the name and compile. It should still work

3. Add these lines at the beginning of paint method.

4. Erase the entire else section from paint.

5. Change the message on the buttons. b1 should say start and b2 should say replay

6. I like my Strings to have meaning to me.
a. I changed the value of the global variable motion to "stop" at the top of the program
b. When b1 is clicked, inside the actionPerformed, change the assignment - motion becomes "go"
c. Inside paint - change the if line to "go"

Compile and make sure the ball is stopped and rolls when you click start.

7. To stop the ball when it gets to the line, we will need to make changes. There are many ways to stop the ball from rolling.
Here is a simple way.

Remove the wrap code, the delay and the repaint. Paste this where the removed lines where - read the comments.

My ball rolls a little too far. Can you fix this problem?

8. To make the replay button to work, add this in the conditional for b2 in the actionPerformed method.
  k = 1;// start k over again

Call me if you need help at this point.

Extra stuff: Bad things happen if you click the replay button while the ball is rolling. Try it.

The sample turns the start and replay button off and on. I used these 2 lines to accomplish that. You will need to figure out where to put them. The replay button doesn't turn on till the ball crosses the line!
Please see if you can figure where they go - you will add them several times.     

b1.setEnabled(false); and        b1.setEnabled(true);

b2.setEnabled(false); and        b2.setEnabled(true);

Knowing how to do this will be worth points in the Unit project

Assignment

Complete Each lab below

You may use it for the Unit project later if you want to. There are notes below the samples.

1. Create each applet

2. In the bug, man and tank samples I have shown you the 3 ( or 4) positions. Please leave those turned on (show the test code) when you get the Lab graded the first time. 

3.  Use code from Lab7d2 to complete the three labs.

 4. Here are some methods to help you get started.

I tested my pictures first to see how they looked
bug1(g,10,10);
bug2(g,90,60);
bug3(g,170,60);

public void bug1(Graphics g, int x, int y)
{
//legs left side
g.setColor(Color.green);
g.drawLine(x+20,y,x+25,y+30);//back leg
g.drawLine(x+35,y,x+25,y+30);//middle leg
g.drawLine(x+25,y+30,x+50,y);//front leg
//legs right side
g.setColor(Color.green);
g.drawLine(x+20,y+60,x+25,y+25);//back leg
g.drawLine(x+25,y+25,x+35,y+60);//middle leg
g.drawLine(x+25,y+30,x+50,y+55);//front leg
//body
g.setColor(Color.yellow);
g.drawOval(x,y+20,50,20);

}

I tested my pictures first to see how they looked
man1(g,20,20);
man2(g,80,20);
man3(g,140,20);
man4(g,200,20);

public void man1(Graphics g, int x, int y)
{
g.setColor(Color.blue);
g.fillOval(x+15,y+5,20,20);
//body
g.drawLine(x+25,y+25,x+25,y+45);
//arms
g.drawLine(x+25,y+30,x,y+35);
g.drawLine(x+25,y+30,x+50,y+35);
//legs
g.drawLine(x+25,y+45,x,y+70);
g.drawLine(x+25,y+45,x+50,y+70);
}

I tested my pictures first to see how they looked
tank1(g,10,50);
tank2(g,70,50);
tank3(g,130,50);

public void tank1(Graphics g, int x, int y)
{
//body
g.setColor(Color.gray);
g.fillRoundRect(0+x, 10+y,50,30,20,20);
g.setColor(Color.gray.darker());
g.fillOval(10+x,10+y,30,30);
//top wheel
g.setColor(Color.black);
g.fillRoundRect(10+x, 5+y,30,5,2,2);
g.setColor(Color.red);
g.fillRect(11+x, 5+y,10,5);

//bottom wheel
g.setColor(Color.black);
g.fillRoundRect(10+x, 40+y,30,5,2,2);
g.setColor(Color.red);
g.fillRect(30+x, 40+y,9,5);

//death ray
g.setColor(Color.yellow);
g.drawLine(25+x,25+y, 60+x,0+y);
g.drawLine(25+x,25+y,60+x,1+y);
g.drawLine(25+x,25+y, 60+x,2+y);
g.drawLine(25+x,25+y, 60+x,3+y);
}