書き方 下記のような感じで android:layout_width の代わりに app:layout_widthPercent が使える android:じゃなくてapp:なので間違えると死ぬ ※ app:部分は任意の文字列が使えますがxmlns:で定義した名前空間と合ってないと死にます <android.support.percent.PercentRelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layou
![Percent Support Libraryを使ってレイアウトを%指定する - Qiita](https://cdn-ak-scissors.b.st-hatena.com/image/square/97055223ce066f82439272efaa9b9dae9107bb97/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-dGV4dD9peGxpYj1yYi00LjAuMCZ3PTk3MiZoPTM3OCZ0eHQ9UGVyY2VudCUyMFN1cHBvcnQlMjBMaWJyYXJ5JUUzJTgyJTkyJUU0JUJEJUJGJUUzJTgxJUEzJUUzJTgxJUE2JUUzJTgzJUFDJUUzJTgyJUE0JUUzJTgyJUEyJUUzJTgyJUE2JUUzJTgzJTg4JUUzJTgyJTkyJUVGJUJDJTg1JUU2JThDJTg3JUU1JUFFJTlBJUUzJTgxJTk5JUUzJTgyJThCJnR4dC1hbGlnbj1sZWZ0JTJDdG9wJnR4dC1jb2xvcj0lMjMyMTIxMjEmdHh0LWZvbnQ9SGlyYWdpbm8lMjBTYW5zJTIwVzYmdHh0LXNpemU9NTYmcz1jNzg2Njk1ZTc1MTdjYzE2YzA0YjgwNTlmNzdlZGRjOA%26mark-x%3D142%26mark-y%3D57%26blend64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZoPTc2Jnc9NzcwJnR4dD0lNDBrb21hdGF0c3UmdHh0LWNvbG9yPSUyMzIxMjEyMSZ0eHQtZm9udD1IaXJhZ2lubyUyMFNhbnMlMjBXNiZ0eHQtc2l6ZT0zNiZ0eHQtYWxpZ249bGVmdCUyQ3RvcCZzPTc4MTVlNDVmY2YwNmM3MjlkM2MwNDcxM2JkNjAxODQ3%26blend-x%3D142%26blend-y%3D486%26blend-mode%3Dnormal%26s%3D936db7722a0c6d0c4a7b456d5f2945f5)