Behaviors

There are three type of behaviors can be used to attached to direct children of CoordinatorLayout.

• RefreshContentBehavior

  • Make nested scrolling content partially visible
  • Add scrolling listeners to observe content view's scrolling offset
  • Add refreshing state listener to observe the refreshing state
  • Add loading state listener to observe the loading state

• RefreshHeaderBehavior

  • Make header view partially visible or totally visible
  • Make header view follow with content view or not
  • Add scrolling listeners to observe header view's scrolling offset
  • Add refreshing state listener to observe the refreshing state

• RefreshFooterBehavior

  • Make footer view partially visible or totally visible
  • Make footer view follow with content view or not
  • Add scrolling listeners to observe footer view's scrolling offset
  • Add loading state listener to observe the loading state

Mode of header and footer behaviors

Follow	Follow Up	Follow Down	Still

When the content view is scrolling, the header and footer can decide whether to follow or not. Four modes are defined:

• Follow: follow with content
• Follow up: follow with content when scrolling up, but not down
• Follow down: follow with content when scrolling down, but not up
• Still: stay still

Samples

Showcases from sample application can be visited in the showcases page.

QuickStart

Attach behaviors in layout

Use content behavior standalone

Just make your nested scrollable view a direct child of CoordinatorLayout, and set the layout_behavior attribute to @string/lr_refresh_content_behavior.

    <androidx.coordinatorlayout.widget.CoordinatorLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/coordinator_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/lr_refresh_content_behavior">
        </androidx.recyclerview.widget.RecyclerView>
    </androidx.coordinatorlayout.widget.CoordinatorLayout>

Work with header and footer view

Below is an example from the sample application, notice that there is an anchored view that is a feature of CoordinatorLayout which make the behaviors more powerful.

    <androidx.coordinatorlayout.widget.CoordinatorLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/coordinator_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <com.androidpi.literefresh.sample.ui.widget.SampleHeaderView
            android:id="@+id/view_header"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_behavior="@string/lr_refresh_header_behavior"
            app:lr_maxOffsetRatio="100%p"
            app:lr_mode="follow"
            app:lr_visibleHeightRatio="50%" />

        <com.androidpi.literefresh.sample.ui.widget.SampleFooterView
            android:id="@+id/view_footer"
            android:layout_width="match_parent"
            android:layout_height="150dp"
            app:layout_behavior="@string/lr_refresh_footer_behavior"
            app:lr_maxOffsetRatio="100%p" />

        <com.androidpi.literefresh.sample.ui.widget.SampleContentView
            android:id="@+id/view_content"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:lr_minOffset="64dp"
            app:layout_behavior="@string/lr_refresh_content_behavior"/>

        <com.androidpi.literefresh.sample.ui.widget.SampleAnchoredView
            android:id="@+id/view_anchored"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_anchor="@id/view_content"
            app:layout_anchorGravity="top|center_horizontal" />
    </androidx.coordinatorlayout.widget.CoordinatorLayout>

Attach behaviors from code

Unlike attach behavior in the layout that you can configure the behavior with attributes. Add behavior through code has some limitations that the configuration is not supported right now, but will be supported soon in a later version.

Set behaviors in CoordinatorLayout.LayoutParams

When using this method you must be sure the layout params has been generated.

    CoordinatorLayout.LayoutParams params = ((CoordinatorLayout.LayoutParams) getLayoutParams());
    RefreshHeaderBehavior headerBehavior = new RefreshHeaderBehavior(context);
    params.setBehavior(headerBehavior);

In this way the configuration should be set with code too. Because we don't use a layout.

Implement interface AttachedBehavior for custom view

If you implement a custom view and want to attach a behavior you can implement the AttachedBehavior interface.

public class RefreshHeaderLayout extends FrameLayout implements CoordinatorLayout.AttachedBehavior{

    protected RefreshHeaderBehavior behavior;

    // ...

    public RefreshHeaderLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        behavior = new RefreshHeaderBehavior(context, attrs);
    }

    @NonNull
    @Override
    public CoordinatorLayout.Behavior getBehavior() {
        return behavior;
    }
}

Supported nested scrolling view

The supported nested scrolling view for content are list below.

View	API level
NestedScrollingView	7
RecyclerView	7
ListView	21

Download

dependencies {
    implementation 'com.androidpi:literefresh:0.10.3'
    implementation 'com.androidpi:literefresh-widgets:0.10.3'
}

Licence

Copyright 2018 yinpinjiu@gmail.com

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.