java将ListView适配器移植到RecyclerView适配器
我想知道如何将我的脚本（mainfeedapter.class）从一个ListView{RecyclerView{
我需要做什么才能让它工作？提前谢谢
我希望我能很好地解释我的问题，否则我会改变它
MainfeedListAdapter。班级
public class MainfeedListAdapter extends ArrayAdapter<Photo> {
private static final String TAG = "MainfeedListAdapter";
private LayoutInflater mInflater;
private int mLayoutResource;
private Context mContext;
private DatabaseReference mReference;
private String currentUsername;
public MainfeedListAdapter(@NonNull Context context, @LayoutRes int resource, @NonNull List<Photo> objects) {
super(context, resource, objects);
mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mLayoutResource = resource;
this.mContext = context;
mReference = FirebaseDatabase.getInstance().getReference();
}
static class Viewholder{
ImageView mProfileImage;
String likesString;
TextView username, timeDelta, caption, likes, liked;
ImageView postImage;
ImageView heartRed, heartWhite;
UserAccountSettings settings = new UserAccountSettings();
User user = new User();
StringBuilder users;
String mLikesString;
boolean likeByCurrentUser;
Heart heart;
GestureDetector detector;
Photo photo;
}
@NonNull
@Override
public View getView(final int position, @Nullable View convertView, @NonNull ViewGroup parent) {
final Viewholder holder;
if(convertView == null){
convertView = mInflater.inflate(mLayoutResource, parent, false);
holder = new Viewholder();
holder.username = (TextView) convertView.findViewById(R.id.display_name);
holder.postImage = (ImageView) convertView.findViewById(R.id.post_image);
holder.caption = (TextView) convertView.findViewById(R.id.image_caption);
holder.timeDelta = (TextView) convertView.findViewById(R.id.image_time_posted);
holder.likes = (TextView) convertView.findViewById(R.id.tvLikesString);
holder.mProfileImage = (ImageView) convertView.findViewById(R.id.f_profile_image);
holder.heartRed = (ImageView) convertView.findViewById(R.id.image_heart_red);
holder.heartWhite = (ImageView) convertView.findViewById(R.id.image_heart_white);
holder.heart = new Heart(holder.heartWhite, holder.heartRed);
holder.liked = (TextView) convertView.findViewById(R.id.likeText);
holder.photo = getItem(position);
holder.detector = new GestureDetector(mContext, new GestureListener(holder));
convertView.setTag(holder);
}else{
holder = (Viewholder) convertView.getTag();
}
getCurrentUsername();
getLikesString(holder);
holder.caption.setText(getItem(position).getCaption());
String timestampDifference = getTimestampDifference(getItem(position));
if(!timestampDifference.equals("0")){
holder.timeDelta.setText(timestampDifference + " DAYS AGO");
}else{
holder.timeDelta.setText("TODAY");
}
final ImageLoader imageLoader = ImageLoader.getInstance();
imageLoader.displayImage(getItem(position).getImage_path(), holder.postImage);
//get the profile image and username
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_user_account_settings))
.orderByChild(mContext.getString(R.string.field_user_id))
.equalTo(getItem(position).getUser_id());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.e(TAG, "onDataChange: OnDataChange ******************************************************************************");
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Log.e(TAG, "onDataChange: found user: "
+ singleSnapshot.getValue(UserAccountSettings.class).getUsername() + "****************************");
holder.username.setText(singleSnapshot.getValue(UserAccountSettings.class).getUsername());
imageLoader.displayImage(singleSnapshot.getValue(UserAccountSettings.class).getProfile_photo(),
holder.mProfileImage);
holder.settings = singleSnapshot.getValue(UserAccountSettings.class);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
Query userQuery = mReference
.child(mContext.getString(R.string.dbname_users))
.orderByChild(mContext.getString(R.string.field_user_id))
.equalTo(getItem(position).getUser_id());
userQuery.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Log.d(TAG, "onDataChange: found user: " +
singleSnapshot.getValue(User.class).getUsername());
holder.user = singleSnapshot.getValue(User.class);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
return convertView;
}
//----------------------------------------Likes---------------------------
public class GestureListener extends GestureDetector.SimpleOnGestureListener{
Viewholder mHolder;
public GestureListener(Viewholder holder) {
mHolder = holder;
}
@Override
public boolean onDown(MotionEvent e) {
return true;
}
@Override
public boolean onDoubleTap(MotionEvent e) {
Log.d(TAG, "onDoubleTap: double tap detected.");
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_photos))
.child(mHolder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes));
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
String keyID = singleSnapshot.getKey();
//case1: Then user already liked the photo
if(mHolder.likeByCurrentUser &&
singleSnapshot.getValue(Like.class).getUser_id()
.equals(FirebaseAuth.getInstance().getCurrentUser().getUid())){
mReference.child(mContext.getString(R.string.dbname_photos))
.child(mHolder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes))
.child(keyID)
.removeValue();
.removeValue();
mReference.child(mContext.getString(R.string.dbname_user_photos))
.child(mHolder.photo.getUser_id())
.child(mHolder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes))
.child(keyID)
.removeValue();
mHolder.heart.toggleLike();
getLikesString(mHolder);
}
//case2: The user has not liked the photo
else if(!mHolder.likeByCurrentUser){
//add new like
addNewLike(mHolder);
break;
}
}
if(!dataSnapshot.exists()){
//add new like
addNewLike(mHolder);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
return true;
}
}
private void addNewLike(final Viewholder holder){
Log.d(TAG, "addNewLike: adding new like");
String newLikeID = mReference.push().getKey();
Like like = new Like();
like.setUser_id(FirebaseAuth.getInstance().getCurrentUser().getUid());
mReference.child(mContext.getString(R.string.dbname_photos))
.child(holder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes))
.child(newLikeID)
.setValue(like);
mReference.child(mContext.getString(R.string.dbname_user_photos))
.child(holder.photo.getUser_id())
.child(holder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes))
.child(newLikeID)
.setValue(like);
holder.heart.toggleLike();
getLikesString(holder);
}
private void getCurrentUsername(){
Log.d(TAG, "getCurrentUsername: retrieving user account settings");
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_users))
.orderByChild(mContext.getString(R.string.field_user_id))
.equalTo(FirebaseAuth.getInstance().getCurrentUser().getUid());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
currentUsername = singleSnapshot.getValue(UserAccountSettings.class).getUsername();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void getLikesString(final Viewholder holder){
Log.d(TAG, "getLikesString: getting likes string");
try{
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_photos))
.child(holder.photo.getPhoto_id())
.child(mContext.getString(R.string.field_likes));
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
holder.users = new StringBuilder();
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
Query query = reference
.child(mContext.getString(R.string.dbname_users))
.orderByChild(mContext.getString(R.string.field_user_id))
.equalTo(singleSnapshot.getValue(Like.class).getUser_id());
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
Log.d(TAG, "onDataChange: found like: " +
singleSnapshot.getValue(User.class).getUsername());
holder.users.append(singleSnapshot.getValue(User.class).getUsername());
holder.users.append(",");
}
String[] splitUsers = holder.users.toString().split(",");
if(holder.users.toString().contains(currentUsername + ",")){//mitch, mitchell.tabian
holder.likeByCurrentUser = true;
}else{
holder.likeByCurrentUser = false;
}
int length = splitUsers.length;
if(length == 1){
holder.likesString = "Liked by " + splitUsers[0];
}
else if(length == 2){
holder.likesString = "Liked by " + splitUsers[0]
+ " and " + splitUsers[1];
}
else if(length == 3){
holder.likesString = "Liked by " + splitUsers[0]
+ ", " + splitUsers[1]
+ " and " + splitUsers[2];
}
else if(length == 4){
holder.likesString = "Liked by " + splitUsers[0]
+ ", " + splitUsers[1]
+ ", " + splitUsers[2]
+ " and " + splitUsers[3];
}
else if(length > 4){
holder.likesString = "Liked by " + splitUsers[0]
+ ", " + splitUsers[1]
+ ", " + splitUsers[2]
+ " and " + (splitUsers.length - 3) + " others";
}
Log.d(TAG, "onDataChange: likes string: " + holder.likesString);
//setup likes string
setupLikesString(holder, holder.likesString);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
if(!dataSnapshot.exists()){
holder.likesString = "";
holder.likeByCurrentUser = false;
//setup likes string
setupLikesString(holder, holder.likesString);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}catch (NullPointerException e){
Log.e(TAG, "getLikesString: NullPointerException: " + e.getMessage() );
holder.likesString = "";
holder.likeByCurrentUser = false;
//setup likes string
setupLikesString(holder, holder.likesString);
}
}
private void setupLikesString(final Viewholder holder, String likesString) {
Log.d(TAG, "setupLikesString: likes string:" + holder.likesString);
if (holder.likeByCurrentUser) {
Log.d(TAG, "setupLikesString: photo is liked by current user");
holder.liked.setText("UnLike");
holder.heartWhite.setVisibility(View.GONE);
holder.heartRed.setVisibility(View.VISIBLE);
holder.heartRed.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
return holder.detector.onTouchEvent(event);
}
});
} else {
Log.d(TAG, "setupLikesString: photo is not liked by current user");
holder.liked.setText("Like");
holder.heartWhite.setVisibility(View.VISIBLE);
holder.heartRed.setVisibility(View.GONE);
holder.heartWhite.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
return holder.detector.onTouchEvent(event);
}
});
}
holder.likes.setText(likesString);
}
//---------------------------------------------end of likes----------------------------
private String getTimestampDifference(Photo photo){
Log.d(TAG, "getTimestampDifference: getting timestamp difference.");
String difference = "";
Calendar c = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.CANADA);
sdf.setTimeZone(TimeZone.getTimeZone("Canada/Pacific"));//google '安卓 list of timezones'
Date today = c.getTime();
sdf.format(today);
Date timestamp;
final String photoTimestamp = photo.getDate_created();
try{
timestamp = sdf.parse(photoTimestamp);
difference = String.valueOf(Math.round(((today.getTime() - timestamp.getTime()) / 1000 / 60 / 60 / 24 )));
}catch (ParseException e){
Log.e(TAG, "getTimestampDifference: ParseException: " + e.getMessage() );
difference = "0";
}
return difference;
}
}
# 1 楼答案
我不知道你说的移植是什么意思，但是如果你有一个listview，现在想使用recycler视图来提高性能。您可以按照这个google sample code和guide for recycler view进行操作。listview和recycler视图的适配器非常相似，因此您可以重用大部分代码