AppBar在滚动时隐藏视图直到折叠
当它到达滚动结束时，我的AppBar隐藏了我的一个视图，但我希望固定视图在AppBar上方，即使它到达滚动结束时。
以下是我开始滚动之前的视图： 
这是完全滚动时的样子： 
您可以看到AppBar左下方的圆形图像现在隐藏在该栏下方。
这是我的片段的XML代码：
<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>
我该如何解决这个问题，使AppBar左下角的圆形图像视图保持在它的上方，即使它到达滚动结束时也是如此？
我今天面临同样的问题，现在我可以修复它。
我必须做的是创建一个像这样的自定义视图：
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());
}
}
}
}
然后在我的布局中使用此自定义视图：
<?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>
我也创建了一个要点：https：//gist.github.com/rodrigohenriques/123f2c6a40b95e00e145
祝你好运哥们。
希望它有帮助。
我也遭受了这个问题。 经过很多的思考，我能够从这种情况中幸存下来。
实际上appbar已经有了高度，这就是为什么它使得所有的视图都能够进入其内部。
所以只需要将app:elevation="0dp" appbar布局即可。 它让所有其他观点自由地保持自身。