【 Android Development for Beginners】 Lesson 3A : Object Oriented Programming - 3

This Notes is according to the udacity free course :

Android Development for Beginners

Lesson 3A : Object Oriented Programming

Resources

What are Java objects

There are 2 easy samples for you to understand what is Java class ?
These are the most important part of this section.

	/**
	* Displays an image, such as an icon.
	*/
	public class ImageView extends View {
	// Resource ID for the source image that should be displayed in the ImageView.
	private int mImageId;
	// Context of the app
	private Context mContext;
	/**
	* Constructs a new ImageView.
	*/
	public ImageView(Context context) {
	mImageId = 0;
	mContext = context;
	}
	/**
	* Sets the source image in the ImageView.
	*
	* @param imageId is the resource ID of the image to be displayed.
	*/
	public void setImage(int imageId) {
	mImageId = imageId;
	}
	}

view raw ImageView.java hosted with ❤ by GitHub

How to create object

1. create object with constructor(regular style)

2. create object with factory methods (need to check out the object documentation)

The quiz focus on too much detail,so I provide the answer for you to check.
TextView textView = new TextView(context);
ImageView img = new ImageView(context);
ToggleButton button = new ToggleButton(context);
Toast toast = Toast.makeText(context, text, duration);


The different between object and class
reference:diffen

class is like a blue map for you to construct object
class can include many state and methods