禁止扩展AppBarLayout [英] Disable expanding of AppBarLayout

问题描述

我有一个带有TabLayout的工具栏和一个包装在CollapsingToolbarLayout内的图像.这个gif几乎可以概括起来:

I have a Toolbar together with a TabLayout and an image wrapped inside a CollapsingToolbarLayout. This gif pretty much sums it up:

https://raw.githubusercontent.com/vitovalov/TabbedCoordinatorLayout/master/art/demo.gif

这是XML:

<?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"
    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="wrap_content"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapse_toolbar"
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <ImageView
                android:id="@+id/header"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@drawable/photo"
                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="100dp"
                android:gravity="top"
                android:minHeight="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:titleMarginTop="15dp"/>

            <android.support.design.widget.TabLayout
                android:id="@+id/tabs"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:layout_gravity="bottom"
                app:tabIndicatorColor="@color/colorAccent"/>

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

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

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

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

我想要实现的是，例如，在选项卡2上，我不想让用户能够看到图像.因此，即使他尝试将AppBarLayout下拉，在任何情况下他都不应该看到该图像.

What I want to achieve is that for instance on Tab 2 I don't want to let the user be able to see the image. So even if he tries to pull the AppBarLayout down he should not see the image under any circumstance.

在显示选项卡2时调用appBarLayout.setExpanded(false);会隐藏图像并将所有内容折叠回去.尽管当您按下AppBarLayout并向下滑动时，您仍可以将图像找回.情况并非如此.

Calling appBarLayout.setExpanded(false); upon showing Tab 2 does hide the image and collapse everything back. Though the moment you press on the AppBarLayout and swipe down you can get the image back. This should not be the case.

如何防止这种行为?

我正在使用v23.1.1的支持库.对于版本22的库，已经有此问题 .但是，该解决方法不再适用于版本23.

I'm using v23.1.1 of the support libraries. For version 22 of the libraryes there's already this question. The workaround is however no longer applicable with version 23.

推荐答案

安妮·克莱尔(Anne-Claire)提供的技巧很有效，但最终导致动画丢失.相反，我要做的是创建一个扩展AppBarLayout.Behavior类的自定义行为，该行为使我​​可以在每次选择时启用/禁用滚动.

The trick provided by Anne-Claire works, but you end up loosing the animation. What I did instead was to create a custom Behavior extending the AppBarLayout.Behavior class that would allow me to enable/disable the scrolling whenever I chose.

public class CustomAppBarLayoutBehavior extends AppBarLayout.Behavior {

    private boolean shouldScroll = false;

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

    @Override
    public boolean onStartNestedScroll(CoordinatorLayout parent, AppBarLayout child, View directTargetChild, View target, int nestedScrollAxes, int type) {
        return shouldScroll;
    }

    @Override
    public boolean onTouchEvent(CoordinatorLayout parent, AppBarLayout child, MotionEvent ev) {
        if(shouldScroll){
            return super.onTouchEvent(parent, child, ev);
        }else{
            return false;
        }
    }

    public void setScrollBehavior(boolean shouldScroll){
        this.shouldScroll = shouldScroll;
    }

    public boolean isShouldScroll(){
        return shouldScroll;
    }
}

然后应将此行为应用于xml布局中的AppBarLayout

You should then apply this behavior to your AppBarLayout in the xml layout

<android.support.design.widget.AppBarLayout
    android:id="@+id/app_bar_layout"
    android:layout_width="wrap_content"
    android:layout_height="@dimen/activity_main_toolbar_height_extended"
    android:theme="@style/ThemeOverlay.AppCompat.Dark"
    android:fitsSystemWindows="true"
    android:elevation="4dp"
    app:layout_behavior="io.eighttails.mvp.widgets.CustomAppBarLayoutBehavior">

然后您可以通过以下操作随意打开和关闭它:

And then you'll be able to switch it on and off as you please by doing:

CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) mAppBarLayout.getLayoutParams();
((CustomAppBarLayoutBehavior)layoutParams.getBehavior()).setScrollBehavior(true);

或

CoordinatorLayout.LayoutParams layoutParams = (CoordinatorLayout.LayoutParams) mAppBarLayout.getLayoutParams();
((CustomAppBarLayoutBehavior)layoutParams.getBehavior()).setScrollBehavior(false);

这篇关于禁止扩展AppBarLayout的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！