Coordinator Layout Behavior
3 likes3,263 views
kyobashi.dex #2の資料です。(Android向け)
Coordinator Layout Behavior
- 2. 自己紹介 釘宮 愼之介 / @kgmyshin ・ Androidエンジニア ・ Androidエンジニア
- 5. 目次 ・ CoordinatorLayoutとは ・ Behaviorとは ・ Behaviorの仕組み ・ すでにあるBehaviorたち ・ カスタムBehaviorを作ってみる
- 14. FloatingActionButton.Behaviorの各メソッドはこのようになってます。(※1 ) public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) { return dependency instanceof Snackbar.SnackbarLayout; } @Override public boolean onDependentViewChanged( CoordinatorLayout parent, FloatingActionButton child, View dependency ) { if (dependency instanceof Snackbar.SnackbarLayout) { updateFabTranslationForSnackbar(parent, child, dependency); } return false; } ※1 説明のために一部ソースを削除してます
- 15. FloatingActionButton.Behaviorの各メソッドはこのようになってます。(※1 ) public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) { return dependency instanceof Snackbar.SnackbarLayout; } @Override public boolean onDependentViewChanged( CoordinatorLayout parent, FloatingActionButton child, View dependency ) { if (dependency instanceof Snackbar.SnackbarLayout) { updateFabTranslationForSnackbar(parent, child, dependency); } return false; } ※1 説明のために一部ソースを削除してます
- 16. FloatingActionButton.Behaviorの各メソッドはこのようになってます。(※1 ) public boolean layoutDependsOn(CoordinatorLayout parent, FloatingActionButton child, View dependency) { return dependency instanceof Snackbar.SnackbarLayout; } @Override public boolean onDependentViewChanged( CoordinatorLayout parent, FloatingActionButton child, View dependency ) { if (dependency instanceof Snackbar.SnackbarLayout) { updateFabTranslationForSnackbar(parent, child, dependency); } return false; } ※1 説明のために一部ソースを削除してます
- 18. AppBarLayout.ScrollingViewBehavior @Override public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) { return dependency instanceof AppBarLayout; }
- 19. @Override public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) { final CoordinatorLayout.Behavior behavior = ((CoordinatorLayout.LayoutParams) dependency.getLayoutParams()).getBehavior(); if (behavior instanceof Behavior) { // Offset the child so that it is below the app-bar (with any overlap) final int appBarOffset = ((Behavior) behavior) .getTopBottomOffsetForScrollingSibling(); final int expandedMax = dependency.getHeight() - mOverlayTop; final int collapsedMin = parent.getHeight() - child.getHeight(); if (mOverlayTop != 0 && dependency instanceof AppBarLayout) { // If we have an overlap top, and the dependency is an AppBarLayout, we control // the offset ourselves based on the appbar's scroll progress. This is so that // the scroll happens sequentially rather than linearly final int scrollRange = ((AppBarLayout) dependency).getTotalScrollRange(); setTopAndBottomOffset(AnimationUtils.lerp(expandedMax, collapsedMin, Math.abs(appBarOffset) / (float) scrollRange)); } else { setTopAndBottomOffset(dependency.getHeight() - mOverlayTop + appBarOffset); } } return false; }
- 20. @Override public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) { final CoordinatorLayout.Behavior behavior = ((CoordinatorLayout.LayoutParams) dependency.getLayoutParams()).getBehavior(); if (behavior instanceof Behavior) { // Offset the child so that it is below the app-bar (with any overlap) final int appBarOffset = ((Behavior) behavior) .getTopBottomOffsetForScrollingSibling(); final int expandedMax = dependency.getHeight() - mOverlayTop; final int collapsedMin = parent.getHeight() - child.getHeight(); if (mOverlayTop != 0 && dependency instanceof AppBarLayout) { // If we have an overlap top, and the dependency is an AppBarLayout, we control // the offset ourselves based on the appbar's scroll progress. This is so that // the scroll happens sequentially rather than linearly final int scrollRange = ((AppBarLayout) dependency).getTotalScrollRange(); setTopAndBottomOffset(AnimationUtils.lerp(expandedMax, collapsedMin, Math.abs(appBarOffset) / (float) scrollRange)); } else { setTopAndBottomOffset(dependency.getHeight() - mOverlayTop + appBarOffset); } } return false; }
- 24. public class CustomBehavior extends CoordinatorLayout.Behavior<View> { public CustomBehavior(Context context, AttributeSet attrs) { } @Override public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) { return dependency instanceof AppBarLayout; } @Override public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) { if (dependency instanceof AppBarLayout) { AppBarLayout appBarLayout = (AppBarLayout) dependency; int totalScrollRange = appBarLayout.getTotalScrollRange(); int scrollY = appBarLayout.getTop(); float ratio = -scrollY / (float) totalScrollRange; child.setAlpha(1.f - ratio); } return true; } }
- 25. public class CustomBehavior extends CoordinatorLayout.Behavior<View> { public CustomBehavior(Context context, AttributeSet attrs) { } @Override public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) { return dependency instanceof AppBarLayout; } @Override public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) { if (dependency instanceof AppBarLayout) { AppBarLayout appBarLayout = (AppBarLayout) dependency; int totalScrollRange = appBarLayout.getTotalScrollRange(); int scrollY = appBarLayout.getTop(); float ratio = -scrollY / (float) totalScrollRange; child.setAlpha(1.f - ratio); } return true; } }
- 26. public class CustomBehavior extends CoordinatorLayout.Behavior<View> { public CustomBehavior(Context context, AttributeSet attrs) { } @Override public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) { return dependency instanceof AppBarLayout; } @Override public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) { if (dependency instanceof AppBarLayout) { AppBarLayout appBarLayout = (AppBarLayout) dependency; int totalScrollRange = appBarLayout.getTotalScrollRange(); int scrollY = appBarLayout.getTop(); float ratio = -scrollY / (float) totalScrollRange; child.setAlpha(1.f - ratio); } return true; } }
- 27. 注意 コンストラクタも実装しよう public CustomBehavior(Context context, AttributeSet attrs) { }
- 29. リフレクションに失敗して落ちます
- 30. まとめ ・ Behaviorを使うと他の子ビューに依存した動きを定義しやすくなります。 ・ 使う場合は大抵 layoutDependsOn とonDependentViewChanged を Overrideすればなんとかなります。
- 32. ご静聴ありがとうございました。