Android 将滚动侦听器添加到RecyclerView适配器
如何实现scroll listener to RecyclerView适配器,以便我可以在活动类上使用。您可以在下面找到我的回收器视图适配器。之所以需要滚动侦听器,是因为我希望在滚动时更改位置。现在,只有单击“回收”视图中的项目,才能更改它Android 将滚动侦听器添加到RecyclerView适配器,android,Android,如何实现scroll listener to RecyclerView适配器,以便我可以在活动类上使用。您可以在下面找到我的回收器视图适配器。之所以需要滚动侦听器,是因为我希望在滚动时更改位置。现在,只有单击“回收”视图中的项目,才能更改它 基本上,我想做的是在activity类中有一个文本视图,当我在recyclerView中滚动时,我应该得到项目的名称 Activity activity; ArrayList<BookData> images = new ArrayLi
基本上,我想做的是在activity类中有一个文本视图,当我在recyclerView中滚动时,我应该得到项目的名称
Activity activity;
ArrayList<BookData> images = new ArrayList<>();
AlbumDBHandler db;
private Context mContext;
public class MyViewHolder extends RecyclerView.ViewHolder {
public ImageView thumbnail;
public TextView name;
public Button button;
public MyViewHolder(View view) {
super(view);
thumbnail = (ImageView) view.findViewById(R.id.thumbnail);
name = (TextView) view.findViewById(R.id.textViewGallery);
button = (Button) view.findViewById(R.id.main_activity_button_carasoul);
}
}
public GalleryAdapter(Context context, ArrayList<BookData> images) {
mContext = context;
this.images = images;
this.db = new AlbumDBHandler(context);
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.gallery_thumbnail, parent, false);
return new MyViewHolder(itemView);
}
@Override
public void onBindViewHolder(final MyViewHolder holder, int position) {
BookData image = images.get(position);
if("".equals(images.get(position).getImageLocalPath())){
Glide.with(mContext)
.load(images.get(position).getImagePath_2())
.thumbnail(0.5f)
.crossFade()
.diskCacheStrategy(DiskCacheStrategy.ALL)
.into(holder.thumbnail);
new ImageDownloaderTask(images.get(position)).execute(images.get(position).getImagePath_2());
}else{
Glide.with(mContext).load(new File(images.get(position).getImageLocalPath())).into(holder.thumbnail);
}
holder.name.setText(images.get(position).getName());
}
class ImageDownloaderTask extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<BookData> bookDataWeakReference;
public ImageDownloaderTask(BookData bookData) {
bookDataWeakReference = new WeakReference<BookData>(bookData);
}
@Override
protected Bitmap doInBackground(String... params) {
return downloadBitmap(params[0]);
}
@Override
protected void onPostExecute(Bitmap bitmap) {
if (isCancelled()) {
bitmap = null;
}
if (bookDataWeakReference != null && bitmap != null) {
BookData bookData = bookDataWeakReference.get();
if (bookData != null){
if (activity instanceof mainActivityCarasoul){
String path = FileUtils.saveBitmapToCamera(activity,bitmap,bookData.getName()+".jpg", BookData.Book).getPath();
bookData.setImageLocalPath(path);
db.updateABook(bookData);
}
}
}
}
private Bitmap downloadBitmap(String url) {
HttpURLConnection urlConnection = null;
try {
URL uri = new URL(url);
urlConnection = (HttpURLConnection) uri.openConnection();
int statusCode = urlConnection.getResponseCode();
if (statusCode != HttpURLConnection.HTTP_OK) {
return null;
}
InputStream inputStream = urlConnection.getInputStream();
if (inputStream != null) {
Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
}
} catch (Exception e) {
urlConnection.disconnect();
Log.w("ImageDownloader", "Error downloading image from " + url);
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
}
return null;
}
}
@Override
public int getItemCount() {
return images.size();
}
public interface ClickListener {
void onClick(View view, int position);
void onLongClick(View view, int position);
}
public static class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {
private GestureDetector gestureDetector;
private GalleryAdapter.ClickListener clickListener;
public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final GalleryAdapter.ClickListener clickListener) {
this.clickListener = clickListener;
gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onSingleTapUp(MotionEvent e) {
return true;
}
@Override
public void onLongPress(MotionEvent e) {
View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
if (child != null && clickListener != null) {
clickListener.onLongClick(child, recyclerView.getChildPosition(child));
}
}
});
}
@Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
View child = rv.findChildViewUnder(e.getX(), e.getY());
if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)) {
clickListener.onClick(child, rv.getChildPosition(child));
}
return false;
}
@Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
}
@Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
}
}
活动;
ArrayList images=新的ArrayList();
数据库;
私有上下文;
公共类MyViewHolder扩展了RecyclerView.ViewHolder{
公共图像视图缩略图;
公共文本视图名称;
公共按钮;
公共MyViewHolder(视图){
超级(视图);
缩略图=(ImageView)view.findViewById(R.id.缩略图);
name=(TextView)view.findViewById(R.id.textViewGallery);
button=(button)view.findViewById(R.id.main\u activity\u button\u);
}
}
公共GalleryAdapter(上下文、ArrayList图像){
mContext=上下文;
这个。图像=图像;
this.db=新的AlbumDBHandler(上下文);
}
@凌驾
公共MyViewHolder onCreateViewHolder(视图组父级,int-viewType){
View itemView=LayoutInflater.from(parent.getContext())
.充气(R.layout.gallery_缩略图,父级,假);
返回新的MyViewHolder(itemView);
}
@凌驾
公共无效onBindViewHolder(最终MyViewHolder,内部位置){
BookData image=images.get(位置);
if(“.”.equals(images.get(position.getImageLocalPath())){
使用(mContext)滑动
.load(images.get(position.getImagePath_2())
.缩略图(0.5f)
.crossFade()
.diskCacheStrategy(diskCacheStrategy.ALL)
.插入(支架.缩略图);
新建ImageDownloaderTask(images.get(position)).execute(images.get(position.getImagePath_2());
}否则{
Glide.with(mContext).load(新文件(images.get(position.getImageLocalPath())).into(holder.缩略图);
}
holder.name.setText(images.get(position.getName());
}
类ImageDownloaderTask扩展异步任务{
私有最终WeakReference bookDataWeakReference;
公共图像下载任务(BookData BookData){
bookDataWeakReference=新的WeakReference(bookData);
}
@凌驾
受保护位图doInBackground(字符串…参数){
返回下载位图(参数[0]);
}
@凌驾
受保护的void onPostExecute(位图){
如果(isCancelled()){
位图=空;
}
if(bookDataWeakReference!=null&&bitmap!=null){
BookData BookData=bookDataWeakReference.get();
如果(bookData!=null){
if(mainActivityCarasoul的活动实例){
String path=FileUtils.saveBitmapToCamera(活动,位图,bookData.getName()+“.jpg”,bookData.Book).getPath();
bookData.setImageLocalPath(路径);
db.UpdateBook(bookData);
}
}
}
}
私有位图下载位图(字符串url){
HttpURLConnection-urlConnection=null;
试一试{
URL uri=新的URL(URL);
urlConnection=(HttpURLConnection)uri.openConnection();
int statusCode=urlConnection.getResponseCode();
if(statusCode!=HttpURLConnection.HTTP\u确定){
返回null;
}
InputStream InputStream=urlConnection.getInputStream();
如果(inputStream!=null){
位图位图=位图工厂.decodeStream(inputStream);
返回位图;
}
}捕获(例外e){
urlConnection.disconnect();
Log.w(“ImageDownloader”,“从“+url”下载图像时出错);
}最后{
if(urlConnection!=null){
urlConnection.disconnect();
}
}
返回null;
}
}
@凌驾
public int getItemCount(){
返回图像。size();
}
公共界面ClickListener{
void onClick(视图,int位置);
仅长按无效(视图,int位置);
}
公共静态类RecyclerTouchListener实现RecyclerView.OnItemTouchListener{
私人手势检测器;
private GalleryAdapter.ClickListener ClickListener;
公共RecyclerTouchListener(上下文上下文、最终RecyclerView RecyclerView、最终GalleryAdapter.ClickListener ClickListener){
this.clickListener=clickListener;
gestureDetector=new gestureDetector(上下文,new gestureDetector.SimpleOnGestureListener()){
@凌驾
公共布尔onSingleTapUp(运动事件e){
返回true;
}
@凌驾
公开无效在线新闻(运动事件e){
View child=recyclerView.findChildViewUnder(e.getX(),e.getY());
if(child!=null&&clickListener!=null){
clickListener.onLongClick(child,recyclerView.getChildPosition(child));
}
}
});
}
@凌驾
公共布尔值onInterceptTouchEvent(RecyclerView rv,MotionEvent e){
View child=rv.findChildViewUnder(e.getX(),e.getY());
if(child!=null&&clickListener!=null&&gestureDetector.onTouchEvent(e)){
单击Listener.onClick(子对象,rv.getC