public class CustomView extends View { public CustomView(Context context) { super(context); } public CustomView(Context context, AttributeSet attrs) { super(context, attrs); } public CustomView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } } onDrawを実装する Viewに描きたい内容はonDrawで記述します。 onDrawはViewが作られたとき、invalidateが呼ばれたときに呼ばれます。 実際にはPaintクラスなどを使ってonDrawメソ
![AndroidのViewに絵を描く - Qiita](https://cdn-ak-scissors.b.st-hatena.com/image/square/b13cfeaadab829ac0d1c160cbf12720362803ef8/height=288;version=1;width=512/https%3A%2F%2Fqiita-user-contents.imgix.net%2Fhttps%253A%252F%252Fcdn.qiita.com%252Fassets%252Fpublic%252Farticle-ogp-background-412672c5f0600ab9a64263b751f1bc81.png%3Fixlib%3Drb-4.0.0%26w%3D1200%26mark64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZ3PTk3MiZoPTM3OCZ0eHQ9QW5kcm9pZCVFMyU4MSVBRVZpZXclRTMlODElQUIlRTclQjUlQjUlRTMlODIlOTIlRTYlOEYlOEYlRTMlODElOEYmdHh0LWFsaWduPWxlZnQlMkN0b3AmdHh0LWNvbG9yPSUyMzIxMjEyMSZ0eHQtZm9udD1IaXJhZ2lubyUyMFNhbnMlMjBXNiZ0eHQtc2l6ZT01NiZzPTcyMjc1N2Q2MzRkOWY5MGEzYzUwNTliMjM0ZTE1Y2M5%26mark-x%3D142%26mark-y%3D57%26blend64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZoPTc2Jnc9NzcwJnR4dD0lNDBuaXR0eWFuJnR4dC1jb2xvcj0lMjMyMTIxMjEmdHh0LWZvbnQ9SGlyYWdpbm8lMjBTYW5zJTIwVzYmdHh0LXNpemU9MzYmdHh0LWFsaWduPWxlZnQlMkN0b3Amcz04YjU4NDBjMjQwM2YxNmNjN2M2NmRhYzY0Mjg4YzExNA%26blend-x%3D142%26blend-y%3D486%26blend-mode%3Dnormal%26s%3D863656164dab846c104980e64c96ecb7)