好的,我的问题与此类似Background image in ListView entries spontaneously disappearing
但此问题已通过在普通 ImageView 上使用 setImageResource 解决,但我希望动画存在于列表的所有元素上,如果没有允许动画运行的自定义 ImageView 类,则无法完成此操作。有谁知道为什么这些图像在 ListView 中滚动后消失,也许如何解决?非常感谢!
这是我的 ListAdapter:
package com.mmgworldwide.layout.listadapters;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import com.mmgworldwide.R;
import com.mmgworldwide.customviews.SpinLoadingAnim;
import com.mmgworldwide.data.FWREvent;
import com.mmgworldwide.data.ImageThreadLoader;
import com.mmgworldwide.data.ImageThreadLoader.ImageLoadedListener;
import com.mmgworldwide.layout.ListDivider;
import com.mmgworldwide.data.Personality;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.AnimationDrawable;
import android.graphics.drawable.Drawable;
import android.text.SpannableString;
import android.text.style.UnderlineSpan;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class PersonalityListAdapter extends ArrayAdapter<Object>{
private Context parentContext;
public ArrayList<Object> items_list_ref;
private ImageThreadLoader imageLoader = new ImageThreadLoader();
public PersonalityListAdapter(Context context, int resource, int textViewResourceId, ArrayList<Object> items_list) {
super(context, resource, textViewResourceId, items_list);
items_list_ref = items_list;
parentContext = context;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Object node = (Object) items_list_ref.get(position);
LayoutInflater inflater = (LayoutInflater) parentContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if(node instanceof ListDivider){
//make new div bar
View div = inflater.inflate(R.layout.list_bar, parent, false);
TextView div_label = (TextView) div.findViewById(R.id.div_label);
div_label.setText(((ListDivider) node).label.toUpperCase());
return div;
}
View row = inflater.inflate(R.layout.picture_list, parent, false);
TextView name_txt = (TextView) row.findViewById(R.id.name_txt);
TextView title_txt = (TextView) row.findViewById(R.id.title_txt);
final ImageView portrait_img = (ImageView) row.findViewById(R.id.portrait);
final ImageView load_cnt = (ImageView) row.findViewById(R.id.portrait_loadDisplay);
name_txt.setText(((Personality) node).getName());
SpannableString title_underlined = new SpannableString(((Personality) node).getTitle());
title_underlined .setSpan(new UnderlineSpan(), 0, title_underlined.length(), 0);
title_txt.setText(title_underlined);
load_cnt.setVisibility(View.VISIBLE);
return row;
}
这是我自定义的 ImageView 类
package com.mmgworldwide.customviews;
import android.R;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.AnimationDrawable;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.ImageView;
public class SpinLoadingAnim extends ImageView{
AnimationDrawable animation;
private final Integer FRAME_SPEED = 20;
public SpinLoadingAnim(Context context, AttributeSet attrs){
super(context, attrs);
//setBackgroundColor(Color.GREEN);
animation = new AnimationDrawable();
animation.addFrame(context.getResources().getDrawable(com.mmgworldwide.R.drawable.spinner_00000), FRAME_SPEED);
animation.addFrame(context.getResources().getDrawable(com.mmgworldwide.R.drawable.spinner_00001), FRAME_SPEED);
animation.addFrame(context.getResources().getDrawable(com.mmgworldwide.R.drawable.spinner_00002), FRAME_SPEED);
animation.addFrame(context.getResources().getDrawable(com.mmgworldwide.R.drawable.spinner_00003), FRAME_SPEED);
animation.setOneShot(false);
this.setBackgroundDrawable(animation);
this.post(new Starter());
}
class Starter implements Runnable {
public void run() {
animation.start();
}
}
这是我的布局 XML
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#FFFFFF"
android:gravity="center_vertical"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp">
<ImageView android:layout_width="60dp" android:layout_height="60dp" android:id="@+id/portrait" android:layout_centerVertical="true"></ImageView>
<com.mmgworldwide.customviews.SpinLoadingAnim
android:id="@+id/portrait_loadDisplay"
android:layout_width="20dp" android:layout_height="20dp"
android:background="#939598"
android:layout_centerVertical="true" android:layout_marginLeft="20dp"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true" />
<ImageView android:layout_height="wrap_content" android:layout_width="wrap_content" android:layout_centerVertical="true" android:id="@+id/arrow" android:src="@drawable/list_arrow" android:layout_alignParentRight="true"></ImageView>
<LinearLayout android:layout_toRightOf="@id/portrait" android:layout_toLeftOf="@id/arrow" android:layout_centerVertical="true" android:orientation="vertical" android:layout_height="wrap_content" android:layout_width="wrap_content" android:baselineAligned="true" android:paddingLeft="15dp" android:paddingRight="15dp">
<TextView android:text="CHEF NAME" android:id="@+id/name_txt" android:layout_width="wrap_content" android:textColor="#000000" android:textStyle="bold"
android:layout_height="wrap_content" android:paddingBottom="2dp" android:textSize="15sp"></TextView>
<TextView android:text="Chef Title" android:id="@+id/title_txt" android:layout_width="wrap_content" android:textColor="#000000"
android:layout_height="wrap_content" android:textSize="13sp"></TextView>
</LinearLayout>
</RelativeLayout>
每 5 个“预加载器”图形仍然消失,但感谢 Michele,这帮了很多忙,让事情变得更干净。
package com.mmgworldwide.layout;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import com.mmgworldwide.R;
import com.mmgworldwide.data.DataConnection;
import com.mmgworldwide.data.ImageThreadLoader;
import com.mmgworldwide.data.Personality;
//http://code.google.com/p/and-conference/source/browse/trunk/src/com/totsp/conference/PresentationList.java
public class Personalities extends Activity{
private ListView listView;
private ArrayAdapter<Object> adapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.personalities);
listView = (ListView) findViewById(R.id.personalitylistview);
listView.setDrawingCacheEnabled(false);
addListAdapter();
setFooterView("more");
}
private void addListAdapter(){
ArrayList<Object> adaptList = makeAdaptList();
adapter = new PersonalityListAdapter(this, 0, adaptList);
listView.setAdapter(adapter);
}
private ArrayList<Object> makeAdaptList(){
ArrayList<Object> adaptList = new ArrayList<Object>();
String currentDivDate = " ";
for(Personality aEvent : DataConnection.fwrInfo.getPersonalityList()){
adaptList.add(aEvent);
}
return adaptList;
}
private void setFooterView(String highlight){
Footer footer = (Footer) findViewById(R.id.footer);
footer.setHighlight(highlight);
}
//***********************************************************************************************************************************************
//ViewHolder
//***********************************************************************************************************************************************
static class ViewHolder {
private TextView tView1;
private TextView tView2;
private ImageView iView1;
}
//***********************************************************************************************************************************************
//PersonalityListAdapter
//***********************************************************************************************************************************************
private class PersonalityListAdapter extends ArrayAdapter<Object>{
LayoutInflater vi = (LayoutInflater) Personalities.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
private Context parentContext;
public ArrayList<Object> items_list_ref;
private ImageThreadLoader imageLoader = new ImageThreadLoader();
public PersonalityListAdapter(final Context context, final int resId, final ArrayList<Object> presentations) {
super(context, resId, presentations);
this.items_list_ref = presentations;
parentContext = context;
}
@Override
public int getCount() {
return items_list_ref.size();
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
//Log.d("TROY", "adding view");
View v = convertView;
if (v == null) {
//Log.d("TROY", "inflation");
v = vi.inflate(R.layout.picture_list, parent, false);
ViewHolder viewHolder = new ViewHolder();
viewHolder.tView1 = (TextView) v.findViewById(R.id.name_txt);
viewHolder.tView2 = (TextView) v.findViewById(R.id.title_txt);
viewHolder.iView1 = (ImageView) v.findViewById(R.id.portrait);
v.setTag(viewHolder);
}
Object p = items_list_ref.get(position);
if (p != null) {
//Log.d("TROY", "setting stuff");
ViewHolder viewHolder = (ViewHolder) v.getTag();
viewHolder.tView1.setText("hi");
}
return v;
}
}
}
这是发生了什么的屏幕截图(为什么没有显示第 5 个预加载图形?):
编辑------
好的,我添加了 getCount 和 getItemId 覆盖,但仍然有同样的问题,我想我会从头开始一个项目,然后只用一个 listView 再试一次,同样的问题,我已经建立了一个测试项目来证明这个令人沮丧的问题。在此测试中,我什至没有向适配器添加任何数据,并且动画仅适用于其中一些适配器,就像我的主项目一样。
非常感谢你的耐心和帮助米歇尔,你非常棒。
最佳答案
ListView 是高度优化的数据结构。您应该使用 ViewHolders 来遵守列表的规则,并使系统的运行更轻松一些。
当您滚动 ListView 时,系统会缓存 Holders 中的项目以提高性能。 阅读How to load the Listview "smoothly" in android
你也可以尝试设置
yourListView.setDrawingCacheEnabled(false);
编辑:好的,而不是尝试用 xml 设置动画
http://developer.android.com/reference/android/graphics/drawable/AnimationDrawable.html
喜欢:
<!-- Animation frames are wheel0.png -- wheel5.png files inside the
res/drawable/ folder -->
<animation-list android:id="selected" android:oneshot="false">
<item android:drawable="@drawable/wheel0" android:duration="50" />
<item android:drawable="@drawable/wheel1" android:duration="50" />
<item android:drawable="@drawable/wheel2" android:duration="50" />
<item android:drawable="@drawable/wheel3" android:duration="50" />
<item android:drawable="@drawable/wheel4" android:duration="50" />
<item android:drawable="@drawable/wheel5" android:duration="50" />
</animation-list>
edit2:请尝试实现 getCount 和 getItemId,你的列表边界有问题,也许 android 无法在滚动后找到列表所在的位置。哦,你能不能用随机数据来测试它,而不是一直都是同一个项目(也许是一些奇怪的散列(默认的 getItemId 实现?)对于相同的项目内容总是相同的)。 例如像这样:
@Override
public int getCount() {
return <yourdatastructure>.getSize();
}
@Override
public long getItemId(int position) {
return position;
}
关于java - 自定义 ImageView 从 ListAdapter 中消失,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/7364569/