Shape Drawable

When you want to dynamically draw some two-dimensional graphics, a ShapeDrawable object will probably suit your needs. With a ShapeDrawable, you can programmatically draw primitive shapes and style them in any way imaginable.

A ShapeDrawable is an extension of Drawable, so you can use one where ever a Drawable is expected — perhaps for the background of a View, set with setBackgroundDrawableO. Of course, you can also draw your shape as its own custom View, to be added to your layout however you please. Because the ShapeDrawable has its own draw() method, you can create a subclass of View that draws the ShapeDrawable during the View.onDraw() method. Here's a basic extension of the View class that does just this, to draw a ShapeDrawable as a View:

public class CustomDrawableView extends View { private ShapeDrawable mDrawable; public CustomDrawableView(Context context) { super(context); int x = 10; int y = 10; int width = 300; int height = 50;

mDrawable = new ShapeDrawable(new OvalShape()); mDrawable.getPaint().setColor(0xff74AC23); mDrawable.setBounds(x, y, x + width, y + height);

protected void onDraw(Canvas canvas) { mDrawable.draw(canvas);

In the constructor, a ShapeDrawable is defines as an OvalShape. It's then given a color and the bounds of the shape are set. If you do not set the bounds, then the shape will not be drawn, whereas if you don't set the color, it will default to black.

With the custom View defined, it can be drawn any way you like. With the sample above, we can draw the shape progammatically in an Activity:

CustomDrawableView mCustomDrawableView; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);

mCustomDrawableView = new CustomDrawableView(this);

setContentView(mCustomDrawableView);

If you'd like to draw this custom drawable from the XML layout instead of from the Activity, then the CustomDrawable class must override the ViewfContext, AttributeSet) constructor, which is called when instantiating a View via inflation from XML. Then add a CustomDrawable element to the XML, like so:

<com.example.shapedrawable.CustomDrawableView android:layout width="fill parent" android:layout_height="wrap_content" />

The ShapeDrawable class (like many other Drawable types in the android.graphics.drawable package) allows you to define various properties of the drawable with public methods. Some properties you might want to adjust include alpha transparency, color filter, dither, opacity and color.

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