Android 为listview和x2B实现了ViewHolder模式;惰性列表图像但仍滚动不平滑
我已经在我的项目中实现了著名的,并且为我的listview实现了ViewHolder模式,但是我的listview的滚动仍然不平滑。我有什么遗漏吗 这是我的密码Android 为listview和x2B实现了ViewHolder模式;惰性列表图像但仍滚动不平滑,android,listview,lazy-loading,Android,Listview,Lazy Loading,我已经在我的项目中实现了著名的,并且为我的listview实现了ViewHolder模式,但是我的listview的滚动仍然不平滑。我有什么遗漏吗 这是我的密码 public View getView(int position, View convertView, ViewGroup parent) { View vi = convertView; // trying to reuse a recycled view ViewHolder holder = nu
public View getView(int position, View convertView, ViewGroup parent) {
View vi = convertView; // trying to reuse a recycled view
ViewHolder holder = null;
if (vi == null) {
vi = inflater.inflate(R.layout.realstate_listview_items,
parent, false);
holder = new ViewHolder();
holder.txtRealstateAddress = (TextView) vi
.findViewById(R.id.txtRealstateAddress);
holder.txtRealstateHomeTypeBroker = (TextView) vi
.findViewById(R.id.txtRealstateHomeTypeBroker);
holder.txtRealstatePrice = (TextView) vi
.findViewById(R.id.txtRealstatePrice);
holder.txtRealStateStatus = (TextView) vi
.findViewById(R.id.txtRealStateStatus);
holder.imgRealstatePhoto = (ImageView) vi
.findViewById(R.id.imgRealstatePhoto);
vi.setTag(holder);
} else {
holder = (ViewHolder) vi.getTag();
}
if (isThreadCompleted) {
if (position == selectedItem) {
View view = (View) holder.txtRealstateAddress.getParent()
.getParent().getParent();
view.setBackgroundColor(Color.parseColor("#BFB495"));
} else {
View view = (View) holder.txtRealstateAddress.getParent()
.getParent().getParent();
view.setBackgroundColor(Color.TRANSPARENT);
}
holder.txtRealstateAddress
.setText(RealStateParsedData.realstate_address
.get(position));
holder.txtRealstateHomeTypeBroker
.setText(RealStateParsedData.realstate_propertytype
.get(position)
+ "\n"
+ RealStateParsedData.realstate_broker
.get(position));
holder.txtRealstatePrice.setText("$"
+ RealStateParsedData.realstate_price.get(position));
holder.txtRealStateStatus.setVisibility(View.VISIBLE);
holder.txtRealStateStatus
.setText(RealStateParsedData.realstate_status
.get(position));
if (RealStateParsedData.realstate_status.get(position).equals(
"Active")) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
holder.txtRealStateStatus.setBackground(getResources()
.getDrawable(
R.drawable.real_estate_text_bg_active));
} else {
holder.txtRealStateStatus
.setBackgroundDrawable(getResources()
.getDrawable(
R.drawable.real_estate_text_bg_active));
}
} else {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
holder.txtRealStateStatus
.setBackground(getResources().getDrawable(
R.drawable.real_estate_text_bg_pending));
} else {
holder.txtRealStateStatus
.setBackgroundDrawable(getResources()
.getDrawable(
R.drawable.real_estate_text_bg_pending));
}
}
imageLoader.DisplayImage(data.get(position),
holder.imgRealstatePhoto);
} else {
holder.txtRealStateStatus.setVisibility(View.INVISIBLE);
}
return vi;
}
}
private static class ViewHolder {
TextView txtRealstateAddress;
TextView txtRealstateHomeTypeBroker;
TextView txtRealstatePrice;
TextView txtRealStateStatus;
ImageView imgRealstatePhoto;
}
更新
ImageLoader类
package com.fedorvlasov.lazylist;
public class ImageLoader {
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews = Collections
.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
Handler handler = new Handler();// handler to display images in UI thread
public ImageLoader(Context context) {
fileCache = new FileCache(context);
executorService = Executors.newFixedThreadPool(5);
}
final int stub_id = R.drawable.img_bg_temp;
public void DisplayImage(String url, ImageView imageView) {
imageViews.put(imageView, url);
Bitmap bitmap = memoryCache.get(url);
if (bitmap != null)
imageView.setImageBitmap(bitmap);
else {
queuePhoto(url, imageView);
imageView.setImageResource(stub_id);
}
}
private void queuePhoto(String url, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url) {
File f = fileCache.getFile(url);
// from SD cache
Bitmap b = decodeFile(f);
if (b != null)
return b;
// from web
try {
Bitmap bitmap = null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) imageUrl
.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
conn.disconnect();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex) {
ex.printStackTrace();
if (ex instanceof OutOfMemoryError)
memoryCache.clear();
return null;
}
}
// decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f) {
try {
// decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream stream1 = new FileInputStream(f);
BitmapFactory.decodeStream(stream1, null, o);
stream1.close();
// Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE = 128;
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 1;
while (true) {
if (width_tmp / 2 < REQUIRED_SIZE
|| height_tmp / 2 < REQUIRED_SIZE)
break;
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
// decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
FileInputStream stream2 = new FileInputStream(f);
Bitmap bitmap = BitmapFactory.decodeStream(stream2, null, o2);
stream2.close();
return bitmap;
} catch (FileNotFoundException e) {
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
// Task for the queue
private class PhotoToLoad {
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad) {
this.photoToLoad = photoToLoad;
}
@Override
public void run() {
try {
if (imageViewReused(photoToLoad))
return;
Bitmap bmp = getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if (imageViewReused(photoToLoad))
return;
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
handler.post(bd);
} catch (Throwable th) {
th.printStackTrace();
}
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag = imageViews.get(photoToLoad.imageView);
if (tag == null || !tag.equals(photoToLoad.url))
return true;
return false;
}
// Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable {
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
bitmap = b;
photoToLoad = p;
}
public void run() {
if (imageViewReused(photoToLoad))
return;
if (bitmap != null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(stub_id);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}
package com.fedorvlasov.lazylist;
公共类图像加载器{
MemoryCache MemoryCache=新的MemoryCache();
文件缓存文件缓存;
私有地图图像视图=集合
.synchronizedMap(新WeakHashMap());
执行服务执行服务;
Handler=new Handler();//在UI线程中显示图像的处理程序
公共图像加载器(上下文){
fileCache=新的fileCache(上下文);
executorService=Executors.newFixedThreadPool(5);
}
最终int存根id=R.drawable.img\u bg\u temp;
public void DisplayImage(字符串url,ImageView){
put(imageView,url);
位图位图=memoryCache.get(url);
if(位图!=null)
设置图像位图(位图);
否则{
队列照片(url、imageView);
setImageResource(存根id);
}
}
私有void队列照片(字符串url,ImageView){
PhotoToLoad p=新的PhotoToLoad(url,imageView);
executorService.submit(新的PhotoLoader(p));
}
私有位图getBitmap(字符串url){
文件f=fileCache.getFile(url);
//从SD缓存
位图b=解码文件(f);
如果(b!=null)
返回b;
//从网络
试一试{
位图=空;
URL imageUrl=新URL(URL);
HttpURLConnection conn=(HttpURLConnection)imageUrl
.openConnection();
连接设置连接超时(30000);
连接设置读取超时(30000);
conn.setInstanceFollowRedirects(真);
InputStream is=conn.getInputStream();
OutputStream os=新文件OutputStream(f);
Utils.CopyStream(is,os);
os.close();
连接断开();
位图=解码文件(f);
返回位图;
}捕获(可丢弃的ex){
例如printStackTrace();
if(ex instanceof OutOfMemoryError)
memoryCache.clear();
返回null;
}
}
//对图像进行解码和缩放以减少内存消耗
私有位图解码文件(文件f){
试一试{
//解码图像大小
BitmapFactory.Options o=新的BitmapFactory.Options();
o、 inJustDecodeBounds=true;
FileInputStream stream1=新的FileInputStream(f);
解码流(stream1,null,o);
stream1.close();
//找到正确的刻度值。它应该是2的幂。
所需最终整型尺寸=128;
内部宽度=o.向外宽度,高度=o.向外高度;
int标度=1;
while(true){
如果(宽度\u tmp/2<要求的\u尺寸
||高度(tmp/2<所需尺寸)
打破
宽度_tmp/=2;
高度_tmp/=2;
比例*=2;
}
//用inSampleSize解码
BitmapFactory.Options o2=新的BitmapFactory.Options();
o2.inSampleSize=刻度;
FileInputStream stream2=新的FileInputStream(f);
位图位图=BitmapFactory.decodeStream(stream2,null,o2);
stream2.close();
返回位图;
}catch(filenotfounde异常){
}捕获(IOE异常){
e、 printStackTrace();
}
返回null;
}
//队列的任务
私有类光电负载{
公共字符串url;
公共影像视图;
公共PhotoToLoad(字符串u,图像视图i){
url=u;
imageView=i;
}
}
类photoloader实现可运行{
光电负载光电负载;
PhotoLoader(PhotoToLoad PhotoToLoad){
this.photoToLoad=photoToLoad;
}
@凌驾
公开募捐{
试一试{
if(图像视图重用(光电加载))
返回;
位图bmp=getBitmap(photoLoad.url);
memoryCache.put(photoload.url,bmp);
if(图像视图重用(光电加载))
返回;
BitmapDisplayer bd=新的BitmapDisplayer(bmp,photoToLoad);
邮政署署长(屋宇署);
}捕获(可丢弃){
th.printStackTrace();
}
}
}
布尔图像视图(PhotoToLoad PhotoToLoad){
String tag=imageViews.get(photoload.imageView);
if(tag==null | |!tag.equals(photoload.url))
返回true;
返回false;
}
//用于在UI线程中显示位图
类BitmapDisplayer实现可运行{
位图;
光电负载光电负载;
公共位图显示器(位图b、PhotoToLoad p){
位图=b;
光电负载=p;
}
公开募捐{
if(图像视图重用(光电加载))
返回;
if(位图!=null)
photoToLoad.imageView.setImageBitmap(位图);
其他的
photoToLoad.imageView.setImageResource(存根id);
}
}
公共void clearCache(){
memoryCache.clear();
fileCache.clear();
}
}
更新2
这是我的房地产_lisview _items.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="match_parent" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:padding="5dp" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/listview_bg" >
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/imgRealstatePhoto"
android:layout_marginLeft="5dp"
android:layout_marginTop="10dp"
android:layout_toLeftOf="@+id/imageView1"
android:layout_toRightOf="@+id/imgRealstatePhoto"
android:orientation="vertical" >
<TextView
android:id="@+id/txtRealstateAddress"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#7D7D7D"
android:textSize="15sp"
android:textStyle="bold" />
<TextView
android:id="@+id/txtRealstateHomeTypeBroker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ellipsize="end"
android:maxLines="3"
android:text="Loading...."
android:textColor="#867C7D"
android:textScaleX="1.025"
android:textSize="12sp" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/linearLayout1"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:layout_below="@+id/linearLayout1"
android:gravity="bottom"
android:orientation="horizontal" >
<TextView
android:id="@+id/txtRealstatePrice"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="0.75"
android:textColor="#006B9E"
android:textSize="12sp"
android:textStyle="bold" />
<TextView
android:id="@+id/txtRealStateStatus"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/real_estate_text_bg_pending"
android:ellipsize="end"
android:gravity="center"
android:maxLines="1"
android:singleLine="true"
android:textColor="@android:color/white"
android:textSize="12sp" />
</LinearLayout>
<ImageView
android:id="@+id/imgRealstatePhoto"
android:layout_width="90dp"
android:layout_height="90dp"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:scaleType="centerCrop"
android:src="@drawable/ellectedofficialsoverlay" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:src="@drawable/expand_ico" />
</RelativeLayout>
</RelativeLayout>
</RelativeLayout>
两件事:
- 看起来您每次都在执行
-RealStateParsedData.realstate\u status.get(position)