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/*
* Copyright (C) 2006 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 android.widget;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
/**
* {@link ViewAnimator} that switches between two views, and has a factory
* from which these views are created. You can either use the factory to
* create the views, or add them yourself. A ViewSwitcher can only have two
* child views, of which only one is shown at a time.
*/
public class ViewSwitcher extends ViewAnimator {
/**
* The factory used to create the two children.
*/
ViewFactory mFactory;
/**
* Creates a new empty ViewSwitcher.
*
* @param context the application's environment
*/
public ViewSwitcher(Context context) {
super(context);
}
/**
* Creates a new empty ViewSwitcher for the given context and with the
* specified set attributes.
*
* @param context the application environment
* @param attrs a collection of attributes
*/
public ViewSwitcher(Context context, AttributeSet attrs) {
super(context, attrs);
}
/**
* {@inheritDoc}
*
* @throws IllegalStateException if this switcher already contains two children
*/
@Override
public void addView(View child, int index, ViewGroup.LayoutParams params) {
if (getChildCount() >= 2) {
throw new IllegalStateException("Can't add more than 2 views to a ViewSwitcher");
}
super.addView(child, index, params);
}
@Override
public CharSequence getAccessibilityClassName() {
return ViewSwitcher.class.getName();
}
/**
* Returns the next view to be displayed.
*
* @return the view that will be displayed after the next views flip.
*/
public View getNextView() {
int which = mWhichChild == 0 ? 1 : 0;
return getChildAt(which);
}
private View obtainView() {
View child = mFactory.makeView();
LayoutParams lp = (LayoutParams) child.getLayoutParams();
if (lp == null) {
lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
}
addView(child, lp);
return child;
}
/**
* Sets the factory used to create the two views between which the
* ViewSwitcher will flip. Instead of using a factory, you can call
* {@link #addView(android.view.View, int, android.view.ViewGroup.LayoutParams)}
* twice.
*
* @param factory the view factory used to generate the switcher's content
*/
public void setFactory(ViewFactory factory) {
mFactory = factory;
obtainView();
obtainView();
}
/**
* Reset the ViewSwitcher to hide all of the existing views and to make it
* think that the first time animation has not yet played.
*/
public void reset() {
mFirstTime = true;
View v;
v = getChildAt(0);
if (v != null) {
v.setVisibility(View.GONE);
}
v = getChildAt(1);
if (v != null) {
v.setVisibility(View.GONE);
}
}
/**
* Creates views in a ViewSwitcher.
*/
public interface ViewFactory {
/**
* Creates a new {@link android.view.View} to be added in a
* {@link android.widget.ViewSwitcher}.
*
* @return a {@link android.view.View}
*/
View makeView();
}
}
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