Mastering CoordinatorLayout Behaviors Dave Smith @devunwired +DaveSmithDev

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AppBarLayout RecyclerView FloatingActionButton SnackbarLayout

@CoordinatorLayout.DefaultBehavior(FooterBarBehavior.class)
 public class FooterBarLayout extends FrameLayout {
 public FooterBarLayout(Context context) {
 super(context);
 } …
 } Behavior Basics

@CoordinatorLayout.DefaultBehavior(FooterBarBehavior.class)
 public class FooterBarLayout extends FrameLayout {
 public FooterBarLayout(Context context) {
 super(context);
 } …
 } Behavior Basics


 
 
 
 Behavior Basics


 
 
 
 Behavior Basics

public class FooterBarBehavior extends CoordinatorLayout.Behavior {
 
 public FooterBarBehavior() {
 //Used when attached to a view class as the default behavior
 }
 
 public FooterBarBehavior(Context context, AttributeSet attrs) {
 super(context, attrs);
 //Used when attached to a view via XML
 } …
 } Type of Attached View Behavior Basics

Layout Behaviors Scrolling Behaviors

Layout Behaviors View A Behavior View B layoutDependsOn() View B View A Behavior onMeasure() onLayout() onMeasureChild() onLayoutChild()

Layout Behaviors View A Behavior View B layoutDependsOn() View B View A Behavior Size/Position Change onDependentViewChanged() onDependentViewRemoved()

@Override
 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);
 } else if (dependency instanceof AppBarLayout) {
 updateFabVisibility(parent, (AppBarLayout) dependency, child);
 } 
 return false;
 } Layout Behaviors

@Override
 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);
 } else if (dependency instanceof AppBarLayout) {
 updateFabVisibility(parent, (AppBarLayout) dependency, child);
 } 
 return false;
 } Layout Behaviors

@Override
 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);
 } else if (dependency instanceof AppBarLayout) {
 updateFabVisibility(parent, (AppBarLayout) dependency, child);
 } 
 return false;
 } Layout Behaviors

@Override
 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);
 } else if (dependency instanceof AppBarLayout) {
 updateFabVisibility(parent, (AppBarLayout) dependency, child);
 } 
 return false;
 } Where did this come from? Layout Behaviors

Layout Behaviors

FAB anchored to AppBarLayout Layout Behaviors

AppBarLayout RecyclerView FloatingActionButton SnackbarLayout layoutDependsOn() app:layout_anchor

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NestedScrollingChild NestedScrollingParent Touch Events Scroll Events Detour: Nested Scrolling

Touch Event Pre-Scroll Scroll Consumed Detour: Nested Scrolling NestedScrollingChild NestedScrollingParent

Touch Event Pre-Scroll Scroll Consumed Detour: Nested Scrolling RecyclerView CoordinatorLayout

Scrolling Behaviors View A Behavior View B NSChild onStartNestedScroll() onNestedPreScroll() onNestedScroll() View A Behavior View B NSChild Touch Scroll

Scrolling Behaviors View A Behavior View B NSChild onNestedPreFling() onNestedFling() onStartNestedScroll() View A Behavior View B NSChild Touch Fling

AppBarLayout RecyclerView FloatingActionButton SnackbarLayout layoutDependsOn() app:layout_anchor NestedScrolling Observer

Mastering CoordinatorLayout Behaviors @devunwired +DaveSmithDev milehighandroid.com wiresareobsolete.com