Group.java
/*
* Copyright (C) 2021 The Android Open Source Project
*
* 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.
*/
package androidx.constraintlayout.widget;
import android.content.Context;
import android.util.AttributeSet;
/**
* Control the visibility and elevation of the referenced views
*
* <b>Added in 1.1</b>
* <p>
* This class controls the visibility of a set of referenced widgets.
* Widgets are referenced by being added to a comma separated list of ids, e.g.:
* <pre>
* {@code
* <androidx.constraintlayout.widget.Group
* android:id="@+id/group"
* android:layout_width="wrap_content"
* android:layout_height="wrap_content"
* android:visibility="visible"
* app:constraint_referenced_ids="button4,button9" />
* }
* </pre>
* <p>
* The visibility of the group will be applied to the referenced widgets.
* It's a convenient way to easily hide/show a set of widgets
* without having to maintain this set
* programmatically.
* <p>
* <h2>Multiple groups</h2>
* <p>
* Multiple groups can reference the same widgets
* -- in that case, the XML declaration order will
* define the final visibility state (the group declared last will have the last word).
* </p>
*/
public class Group extends ConstraintHelper {
public Group(Context context) {
super(context);
}
public Group(Context context, AttributeSet attrs) {
super(context, attrs);
}
public Group(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
/**
*
* @param attrs
*/
@Override
protected void init(AttributeSet attrs) {
super.init(attrs);
mUseViewMeasure = false;
}
@Override
public void onAttachedToWindow() {
super.onAttachedToWindow();
applyLayoutFeatures();
}
@Override
public void setVisibility(int visibility) {
super.setVisibility(visibility);
applyLayoutFeatures();
}
@Override
public void setElevation(float elevation) {
super.setElevation(elevation);
applyLayoutFeatures();
}
/**
*
* @param container
*/
@Override
protected void applyLayoutFeaturesInConstraintSet(ConstraintLayout container) {
applyLayoutFeatures(container);
}
/**
*
* @param container
*/
@Override
public void updatePostLayout(ConstraintLayout container) {
ConstraintLayout.LayoutParams params = (ConstraintLayout.LayoutParams) getLayoutParams();
params.mWidget.setWidth(0);
params.mWidget.setHeight(0);
}
}