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/*
* Copyright (C) 2013 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 com.example.android.listviewanimations;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ObjectAnimator;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.ListView;
/**
* This example shows how animating ListView items can lead to problems as views are recycled,
* and how to perform these types of animations correctly with new API added in Jellybean.
*
* Watch the associated video for this demo on the DevBytes channel of developer.android.com
* or on YouTube at https://www.youtube.com/watch?v=8MIfSxgsHIs.
*/
public class ListViewAnimations extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_view_animations);
final CheckBox vpaCB = (CheckBox) findViewById(R.id.vpaCB);
final CheckBox setTransientStateCB = (CheckBox) findViewById(R.id.setTransientStateCB);
final ListView listview = (ListView) findViewById(R.id.listview);
final ArrayList<String> cheeseList = new ArrayList<String>();
for (int i = 0; i < Cheeses.sCheeseStrings.length; ++i) {
cheeseList.add(Cheeses.sCheeseStrings[i]);
}
final StableArrayAdapter adapter = new StableArrayAdapter(this,
android.R.layout.simple_list_item_1, cheeseList);
listview.setAdapter(adapter);
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, final View view, int position, long id) {
final String item = (String) parent.getItemAtPosition(position);
if (vpaCB.isChecked()) {
view.animate().setDuration(1000).alpha(0).
withEndAction(new Runnable() {
@Override
public void run() {
cheeseList.remove(item);
adapter.notifyDataSetChanged();
view.setAlpha(1);
}
});
} else {
// Here's where the problem starts - this animation will animate a View object.
// But that View may get recycled if it is animated out of the container,
// and the animation will continue to fade a view that now contains unrelated
// content.
ObjectAnimator anim = ObjectAnimator.ofFloat(view, View.ALPHA, 0);
anim.setDuration(1000);
if (setTransientStateCB.isChecked()) {
// Here's the correct way to do this: if you tell a view that it has
// transientState, then ListView ill avoid recycling it until the
// transientState flag is reset.
// A different approach is to use ViewPropertyAnimator, which sets the
// transientState flag internally.
view.setHasTransientState(true);
}
anim.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
cheeseList.remove(item);
adapter.notifyDataSetChanged();
view.setAlpha(1);
if (setTransientStateCB.isChecked()) {
view.setHasTransientState(false);
}
}
});
anim.start();
}
}
});
}
private class StableArrayAdapter extends ArrayAdapter<String> {
HashMap<String, Integer> mIdMap = new HashMap<String, Integer>();
public StableArrayAdapter(Context context, int textViewResourceId,
List<String> objects) {
super(context, textViewResourceId, objects);
for (int i = 0; i < objects.size(); ++i) {
mIdMap.put(objects.get(i), i);
}
}
@Override
public long getItemId(int position) {
String item = getItem(position);
return mIdMap.get(item);
}
@Override
public boolean hasStableIds() {
return true;
}
}
}
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