如果您只想要平滑滚动,则不需要自定义滚动,正如我在其他帖子中提到的那样。
每当您想要开始平滑滚动时,请添加以下行。
appBarLayout.setExpanded(false, /*true if animation required else false*/true)
recyclerView.smoothScrollToPosition(position)
额外信息
此外,我在您的布局中没有看到任何 RecyclerView
,有可能您将其放在了 LinearLayout
中,而这又是 CollapsingToolbarLayout
的一部分。我完全不知道为什么您将 RecyclerView
放在 CollapsingToolbarLayout
中。我会给出一个简化的布局,这是我正在使用的。
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.CoordinatorLayout
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:id="@+id/app_bar_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:expanded="true"
app:layout_behavior="com.company.app.custom.CustomRecyclerScrollBehavior">
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:contentScrim="?attr/colorPrimary"
app:expandedTitleMarginEnd="64dp"
app:expandedTitleMarginStart="48dp"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<FrameLayout
android:id="@+id/header_frame"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_collapseMode="parallax"
app:layout_collapseParallaxMultiplier="0.8">
<com.company.app.custom.CustomViewPager
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:calculation="height"
app:height_ratio="@integer/product_listitem_img_width_ratio"
app:width_ratio="@integer/product_listitem_img_height_ratio" />
<com.company.app.custom.CustomImageView
android:id="@+id/img_stock_layer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="fitXY"
android:src="@color/transparent_app_black"
android:visibility="gone"
app:calculation_type="height"
app:ratio_height="@integer/product_listitem_img_width_ratio"
app:ratio_width="@integer/product_listitem_img_height_ratio" />
<com.inneex.www.customfonts.FontTextView
android:id="@+id/lbl_out_of_stock"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="@string/out_of_stock"
android:textColor="?android:attr/textColorPrimaryInverse"
android:textSize="13sp"
android:visibility="gone"
app:customFont="@string/font_ss_semibold" />
<LinearLayout
android:id="@+id/ll_page"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center_horizontal"
android:orientation="horizontal"
android:paddingBottom="@dimen/inspire_detail_oval_margin_bottom" />
</FrameLayout>
<android.support.v7.widget.Toolbar
android:id="@+id/main_toolbar"
android:layout_width="match_parent"
android:layout_height="@dimen/toolbar_height"
android:background="?attr/colorPrimary"
app:layout_anchor="@id/header_frame"
app:layout_collapseMode="pin"
app:title="">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal">
<com.inneex.www.customfonts.FontTextView
android:id="@+id/lbl_toolbar_product_name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_weight="1"
android:ellipsize="end"
android:lines="1"
android:maxLines="1"
android:minLines="1"
android:textColor="?android:attr/textColorPrimary"
android:textSize="18sp"
app:customFont="@string/font_ss_semibold" />
</LinearLayout>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<ImageView
android:id="@+id/img_back"
android:layout_width="@dimen/toolbar_height"
android:layout_height="@dimen/toolbar_height"
android:layout_gravity="top|start"
android:scaleType="fitXY"
android:src="@drawable/back"
app:layout_collapseMode="parallax" />
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
<include
layout="@layout/listitem_product_detail_buy_cheap"
android:layout_width="match_parent"
android:layout_height="@dimen/product_detail_button_buy_cheap_height"
android:layout_alignParentBottom="true"
android:layout_gravity="bottom" />
</RelativeLayout>
header_frame
是一个FrameLayout
,负责大工具栏的折叠滚动。带有id main_toolbar
的Toolbar
负责工具栏的折叠视图。下面是AppBarLayout
和RecyclerView
。ImageView
用于返回按钮,一旦折叠的Toolbar
显示出来,它就会被显示。
为了使滚动流畅,我添加了CustomRecyclerScrollBehavior
,这是我之前与您讨论过的内容。
import android.content.Context;
import android.support.design.widget.AppBarLayout;
import android.support.design.widget.CoordinatorLayout;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.Map;
public class CustomRecyclerScrollBehavior extends AppBarLayout.Behavior {
private Map<RecyclerView, RecyclerViewScrollListener> scrollListenerMap = new HashMap<>();
public CustomRecyclerScrollBehavior() {
}
public CustomRecyclerScrollBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, float velocityX, float velocityY, boolean consumed) {
if (target instanceof RecyclerView) {
final RecyclerView recyclerView = (RecyclerView) target;
if (scrollListenerMap.get(recyclerView) == null) {
RecyclerViewScrollListener recyclerViewScrollListener = new RecyclerViewScrollListener(coordinatorLayout, child, this);
scrollListenerMap.put(recyclerView, recyclerViewScrollListener);
recyclerView.addOnScrollListener(recyclerViewScrollListener);
}
scrollListenerMap.get(recyclerView).setVelocity(velocityY);
consumed = scrollListenerMap.get(recyclerView).getScrolledY() > 0;
}
return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
}
private static class RecyclerViewScrollListener extends RecyclerView.OnScrollListener {
private int scrolledY;
private boolean dragging;
private float velocity;
private WeakReference<CoordinatorLayout> coordinatorLayoutRef;
private WeakReference<AppBarLayout> childRef;
private WeakReference<CustomRecyclerScrollBehavior> behaviorWeakReference;
public RecyclerViewScrollListener(CoordinatorLayout coordinatorLayout, AppBarLayout child, CustomRecyclerScrollBehavior barBehavior) {
coordinatorLayoutRef = new WeakReference<>(coordinatorLayout);
childRef = new WeakReference<>(child);
behaviorWeakReference = new WeakReference<>(barBehavior);
}
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
dragging = newState == RecyclerView.SCROLL_STATE_DRAGGING;
}
public void setVelocity(float velocity) {
this.velocity = velocity;
}
public int getScrolledY() {
return scrolledY;
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
scrolledY += dy;
if (scrolledY <= 0 && !dragging && childRef.get() != null && coordinatorLayoutRef.get() != null && behaviorWeakReference.get() != null) {
behaviorWeakReference.get().onNestedFling(coordinatorLayoutRef.get(), childRef.get(), recyclerView, 0, velocity, false);
}
}
}
}
这个类用于维护在嵌套滚动中RecyclerView
的滚动速度。它的fling已经在此处更改。
希望这对你有帮助!
LinearLayout
中添加这个属性android:descendantFocusability="blocksDescendants"
。 - Harshad PansuriyarecycleView.post(new Runnable() { public void run() { recycleView.smoothScrollToPosition(80); });
- Blackbelt