Common Views

There's many different types of views, but a few are used a lot more than others. Understanding those basic views is a pretty important step in learning Android. We'll go over those quickly in this lesson.

TextViews

TextViews are one of the most simple views-- All they do is render some text on the screen. You can use the setText() method if you want to set the text inside your activity. This is great for situations where you need to update the label based on something the user has done.

Here's some of the more common attributes:

Attribute	Effect
text	The text value to show in the TextView
textStyle	The style of front to use (e.g. bold/italic)
fontFamily	The font to use for the text
textAlignment	How to align the text within the view (center, left, top, etc...)

Buttons

Buttons are a pretty common part of any android app. Just like a textView, they have a text value which is displayed over the button. Clicking a button will do nothing by default, but you can register a callback using setOnClickListener().

myButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        //This will be run when the user clicks a button
        myButton.setText("You clicked me!");
    }
});

Another common method is setEnabled() , which allows you to mark the button as either enabled or disabled. This is great for times when you want to disable a button until something else happens. For example, you might want to disable a login button until after a user has entered their password in another field.

It's actually possible to define a callback using the onClick property in the button's layout file. However, it's generally preferred to use setOnClickListener() since it works with older devices and keeps all your business logic on one place.

EditTexts

EditTexts are editable text boxes that the user can type in. These are great for accepting any type of text-based user input like emails or passwords.

Typically EditTexts don't have much behavior on their own. Instead, you usually just read their values from some other callback with getText(). One quirk of EditTexts is that the getText() method actually returns an Editable object instead of a string, but you can use toString() to easily convert it. Like a button, you can use setEnabled() to lock or unlock the textview for editing.

String myText = myEditText.getText().toString();
myTextView.setText("The user entered" + myText);

Here's some of the more common attributes:

Attribute	Effect
hint	The "hint" text to show before the user starts typing
inputType	The type of input (e.g. number, text, password,email). Android will show the appropriate keyboard type.
maxLines	The number of lines in the input box (defaults to 1)