AppBar hides view when scrolling until collapsed

2019-04-07 13:41发布

站内文章 / Android
37 0 0

问题:

My AppBar hides one of my views right when it reaches the end of the scrolling, but I want the pinned view to stay above the AppBar even when it reaches the end of its scrolling.

Here is what my view looks like before I start scrolling:

And this is what it looks like when it is fully scrolled:

You can see that the circular image on the bottom left of the AppBar is now hidden under the bar.

Here is my fragment's XML code:

<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="@color/translucent"
            app:expandedTitleMarginEnd="64dp"
            app:expandedTitleMarginStart="48dp"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <ImageView
                android:id="@+id/backdrop"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@color/dark_gray"
                android:fitsSystemWindows="true"
                android:scaleType="centerCrop"
                app:layout_collapseMode="parallax" />

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

        </android.support.design.widget.CollapsingToolbarLayout>

    </android.support.design.widget.AppBarLayout>


    <android.support.v4.widget.NestedScrollView
        ...
    </android.support.v4.widget.NestedScrollView>


    <de.hdodenhof.circleimageview.CircleImageView
        android:id="@+id/profile_image"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_margin="16dp"
        android:fitsSystemWindows="true"
        android:src="@drawable/default_profile"
        app:border_color="@android:color/white"
        app:border_width="2dp"
        app:layout_anchor="@id/appbar"
        app:layout_anchorGravity="bottom|left|end" />

    <android.support.design.widget.FloatingActionButton
        ... 
    />

</android.support.design.widget.CoordinatorLayout>

How do I fix this so that the circular imageview on the bottom left of the AppBar stays above it even when it reaches the end of its scrolling?

回答1:

I was facing the same issue as you today and I could fix it right now.

What I had to do was create a custom view like this:

package com.github.rodrigohenriques.samples.customview;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.graphics.RectF;
import android.os.Build;
import android.support.design.widget.AppBarLayout;
import android.support.design.widget.CoordinatorLayout;
import android.support.design.widget.Snackbar;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewPropertyAnimatorListener;
import android.support.v4.view.animation.FastOutSlowInInterpolator;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.widget.ImageView;

import java.util.List;

@CoordinatorLayout.DefaultBehavior(CoordinatedImageView.Behavior.class)
public class CoordinatedImageView extends ImageView {

    private boolean mIsHiding;

    public CoordinatedImageView(Context context) {
        super(context);
    }

    public CoordinatedImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CoordinatedImageView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public CoordinatedImageView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    public void hide() {
        if(!this.mIsHiding && this.getVisibility() == VISIBLE) {
            if(ViewCompat.isLaidOut(this) && !this.isInEditMode()) {
                this.animate().scaleX(0.0F).scaleY(0.0F).alpha(0.0F).setDuration(200L).setInterpolator(new FastOutSlowInInterpolator()).setListener(new AnimatorListenerAdapter() {
                    public void onAnimationStart(Animator animation) {
                        CoordinatedImageView.this.mIsHiding = true;
                        CoordinatedImageView.this.setVisibility(VISIBLE);
                    }

                    public void onAnimationCancel(Animator animation) {
                        CoordinatedImageView.this.mIsHiding = false;
                    }

                    public void onAnimationEnd(Animator animation) {
                        CoordinatedImageView.this.mIsHiding = false;
                        CoordinatedImageView.this.setVisibility(GONE);
                    }
                });
            } else {
                this.setVisibility(GONE);
            }
        }
    }

    public void show() {
        if(this.getVisibility() != VISIBLE) {
            if(ViewCompat.isLaidOut(this) && !this.isInEditMode()) {
                this.setAlpha(0.0F);
                this.setScaleY(0.0F);
                this.setScaleX(0.0F);
                this.animate().scaleX(1.0F).scaleY(1.0F).alpha(1.0F).setDuration(200L).setInterpolator(new FastOutSlowInInterpolator()).setListener(new AnimatorListenerAdapter() {
                    public void onAnimationStart(Animator animation) {
                        CoordinatedImageView.this.setVisibility(VISIBLE);
                    }
                });
            } else {
                this.setVisibility(VISIBLE);
                this.setAlpha(1.0F);
                this.setScaleY(1.0F);
                this.setScaleX(1.0F);
            }
        }
    }

    public static class Behavior extends android.support.design.widget.CoordinatorLayout.Behavior<CoordinatedImageView> {
        private static final boolean SNACKBAR_BEHAVIOR_ENABLED;
        private Rect mTmpRect;

        public Behavior() {
        }

        public boolean layoutDependsOn(CoordinatorLayout parent, CoordinatedImageView child, View dependency) {
            return SNACKBAR_BEHAVIOR_ENABLED && dependency instanceof Snackbar.SnackbarLayout;
        }

        public boolean onDependentViewChanged(CoordinatorLayout parent, CoordinatedImageView child, View dependency) {
            if(dependency instanceof Snackbar.SnackbarLayout) {
                this.updateFabTranslationForSnackbar(parent, child, dependency);
            } else if(dependency instanceof AppBarLayout) {
                this.updateFabVisibility(parent, (AppBarLayout)dependency, child);
            }

            return false;
        }

        public void onDependentViewRemoved(CoordinatorLayout parent, CoordinatedImageView child, View dependency) {
            if(dependency instanceof Snackbar.SnackbarLayout && ViewCompat.getTranslationY(child) != 0.0F) {
                ViewCompat.animate(child).translationY(0.0F).scaleX(1.0F).scaleY(1.0F).alpha(1.0F).setInterpolator(new FastOutSlowInInterpolator()).setListener((ViewPropertyAnimatorListener)null);
            }

        }

        private boolean updateFabVisibility(CoordinatorLayout parent, AppBarLayout appBarLayout, CoordinatedImageView child) {
            CoordinatorLayout.LayoutParams lp = (CoordinatorLayout.LayoutParams)child.getLayoutParams();
            if(lp.getAnchorId() != appBarLayout.getId()) {
                return false;
            } else {
                if(this.mTmpRect == null) {
                    this.mTmpRect = new Rect();
                }

                Rect rect = this.mTmpRect;
                ViewGroupUtils.getDescendantRect(parent, appBarLayout, rect);
                if(rect.bottom <= getMinimumHeightForVisibleOverlappingContent(appBarLayout)) {
                    child.hide();
                } else {
                    child.show();
                }

                return true;
            }
        }

        private int getMinimumHeightForVisibleOverlappingContent(AppBarLayout appBarLayout) {
            int minHeight = ViewCompat.getMinimumHeight(appBarLayout);
            if(minHeight != 0) {
                return minHeight * 2;
            } else {
                int childCount = appBarLayout.getChildCount();
                return childCount >= 1?ViewCompat.getMinimumHeight(appBarLayout.getChildAt(childCount - 1)) * 2 :0;
            }
        }

        private void updateFabTranslationForSnackbar(CoordinatorLayout parent, CoordinatedImageView imageView, View snackbar) {
            if(imageView.getVisibility() == 0) {
                float translationY = this.getFabTranslationYForSnackbar(parent, imageView);
                ViewCompat.setTranslationY(imageView, translationY);
            }
        }

        private float getFabTranslationYForSnackbar(CoordinatorLayout parent, CoordinatedImageView imageView) {
            float minOffset = 0.0F;
            List dependencies = parent.getDependencies(imageView);
            int i = 0;

            for(int z = dependencies.size(); i < z; ++i) {
                View view = (View)dependencies.get(i);
                if(view instanceof Snackbar.SnackbarLayout && parent.doViewsOverlap(imageView, view)) {
                    minOffset = Math.min(minOffset, ViewCompat.getTranslationY(view) - (float)view.getHeight());
                }
            }

            return minOffset;
        }

        public boolean onLayoutChild(CoordinatorLayout parent, CoordinatedImageView child, int layoutDirection) {
            List dependencies = parent.getDependencies(child);
            int i = 0;

            for(int count = dependencies.size(); i < count; ++i) {
                View dependency = (View)dependencies.get(i);
                if(dependency instanceof AppBarLayout && this.updateFabVisibility(parent, (AppBarLayout)dependency, child)) {
                    break;
                }
            }

            parent.onLayoutChild(child, layoutDirection);
            this.offsetIfNeeded(parent, child);
            return true;
        }

        private void offsetIfNeeded(CoordinatorLayout parent, CoordinatedImageView imageView) {
            Rect padding = new Rect(imageView.getPaddingLeft(), imageView.getPaddingTop(), imageView.getPaddingRight(), imageView.getPaddingBottom());
            if(padding.centerX() > 0 && padding.centerY() > 0) {
                CoordinatorLayout.LayoutParams lp = (CoordinatorLayout.LayoutParams)imageView.getLayoutParams();
                int offsetTB = 0;
                int offsetLR = 0;
                if(imageView.getRight() >= parent.getWidth() - lp.rightMargin) {
                    offsetLR = padding.right;
                } else if(imageView.getLeft() <= lp.leftMargin) {
                    offsetLR = -padding.left;
                }

                if(imageView.getBottom() >= parent.getBottom() - lp.bottomMargin) {
                    offsetTB = padding.bottom;
                } else if(imageView.getTop() <= lp.topMargin) {
                    offsetTB = -padding.top;
                }

                imageView.offsetTopAndBottom(offsetTB);
                imageView.offsetLeftAndRight(offsetLR);
            }

        }

        static {
            SNACKBAR_BEHAVIOR_ENABLED = Build.VERSION.SDK_INT >= 11;
        }
    }

    private static class ViewGroupUtils {
        private static final ViewGroupUtils.ViewGroupUtilsImpl IMPL;

        ViewGroupUtils() {
        }

        static void offsetDescendantRect(ViewGroup parent, View descendant, Rect rect) {
            IMPL.offsetDescendantRect(parent, descendant, rect);
        }

        static void getDescendantRect(ViewGroup parent, View descendant, Rect out) {
            out.set(0, 0, descendant.getWidth(), descendant.getHeight());
            offsetDescendantRect(parent, descendant, out);
        }

        static {
            int version = Build.VERSION.SDK_INT;
            if(version >= 11) {
                IMPL = new ViewGroupUtils.ViewGroupUtilsImplHoneycomb();
            } else {
                IMPL = new ViewGroupUtils.ViewGroupUtilsImplBase();
            }

        }

        private static class ViewGroupUtilsImplHoneycomb implements ViewGroupUtils.ViewGroupUtilsImpl {
            private ViewGroupUtilsImplHoneycomb() {
            }

            public void offsetDescendantRect(ViewGroup parent, View child, Rect rect) {
                ViewGroupUtilsHoneycomb.offsetDescendantRect(parent, child, rect);
            }
        }

        private static class ViewGroupUtilsImplBase implements ViewGroupUtils.ViewGroupUtilsImpl {
            private ViewGroupUtilsImplBase() {
            }

            public void offsetDescendantRect(ViewGroup parent, View child, Rect rect) {
                parent.offsetDescendantRectToMyCoords(child, rect);
            }
        }

        private interface ViewGroupUtilsImpl {
            void offsetDescendantRect(ViewGroup var1, View var2, Rect var3);
        }
    }

    private static class ViewGroupUtilsHoneycomb {
        private static final ThreadLocal<Matrix> sMatrix = new ThreadLocal();
        private static final ThreadLocal<RectF> sRectF = new ThreadLocal();
        private static final Matrix IDENTITY = new Matrix();

        ViewGroupUtilsHoneycomb() {
        }

        public static void offsetDescendantRect(ViewGroup group, View child, Rect rect) {
            Matrix m = (Matrix)sMatrix.get();
            if(m == null) {
                m = new Matrix();
                sMatrix.set(m);
            } else {
                m.set(IDENTITY);
            }

            offsetDescendantMatrix(group, child, m);
            RectF rectF = (RectF)sRectF.get();
            if(rectF == null) {
                rectF = new RectF();
            }

            rectF.set(rect);
            m.mapRect(rectF);
            rect.set((int)(rectF.left + 0.5F), (int)(rectF.top + 0.5F), (int)(rectF.right + 0.5F), (int)(rectF.bottom + 0.5F));
        }

        static void offsetDescendantMatrix(ViewParent target, View view, Matrix m) {
            ViewParent parent = view.getParent();
            if(parent instanceof View && parent != target) {
                View vp = (View)parent;
                offsetDescendantMatrix(target, vp, m);
                m.preTranslate((float)(-vp.getScrollX()), (float)(-vp.getScrollY()));
            }

            m.preTranslate((float)view.getLeft(), (float)view.getTop());
            if(!view.getMatrix().isIdentity()) {
                m.preConcat(view.getMatrix());
            }

        }
    }
}

And then use this custom view in my layout:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context=".ScrollingActivity">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/app_bar"
        android:layout_width="match_parent"
        android:layout_height="@dimen/app_bar_height"
        android:fitsSystemWindows="true"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/toolbar_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <ImageView
                android:id="@+id/backdrop"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:scaleType="centerCrop"
                android:fitsSystemWindows="true"
                android:src="@drawable/image"
                app:layout_collapseMode="parallax" />

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/AppTheme.PopupOverlay" />

        </android.support.design.widget.CollapsingToolbarLayout>
    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_scrolling" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email"
        app:layout_anchor="@id/app_bar"
        app:layout_anchorGravity="bottom|end" />

    <com.github.rodrigohenriques.samples.customview.CoordinatedImageView
        android:id="@+id/logo"
        android:layout_width="72dp"
        android:layout_height="72dp"
        android:scaleType="centerCrop"
        android:src="@drawable/image"
        android:layout_margin="@dimen/fab_margin"
        app:layout_anchor="@id/app_bar"
        app:layout_anchorGravity="bottom|start" />

</android.support.design.widget.CoordinatorLayout>

I also created a gist: https://gist.github.com/rodrigohenriques/123f2c6a40b95e00e145

Good luck to you buddy.

Hope that it helps.



回答2:

i was also suffered from this problem. After lots of thinking i was able to survived from that situation.

Actually the appbar is already having the elevation that's why it makes all the views to gets inside of itself.

So just you need to give app:elevation="0dp" to the appbar layout. It gives all other views freedom to stay over itself.



标签： android android-layout android-support-library android-toolbar android-coordinatorlayout
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