android - 从适配器单击时,如何在 RecyclerView 中获取所选位置?
问题描述
我正在开发一个应用程序,我希望它滚动到我从适配器单击到另一个活动的特定位置,例如检查个人资料片段中较小图片并滚动到另一个活动中的确切位置的 Instagram 方式,即从小图到大图。
我的适配器代码
public class DisplayDuetAdapter extends RecyclerView.Adapter<DisplayDuetAdapter.ImageViewHolder> {
private Context mContext;
private List<DisplayDuet> mDisplayDuet;
public int position;
public int getPosition() {
return position;
}
public void setPosition(int position) {
this.position = position;
}
public DisplayDuetAdapter(Context context, List<DisplayDuet> displayDuet){
mContext = context;
mDisplayDuet = displayDuet;
}
@NonNull
@Override
public DisplayDuetAdapter.ImageViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(mContext).inflate(R.layout.duet_display_item, viewGroup, false);
return new DisplayDuetAdapter.ImageViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull final DisplayDuetAdapter.ImageViewHolder imageViewHolder, int i) {
final DisplayDuet displayDuet = mDisplayDuet.get(i);
// Glide.with(mContext).load(displayDuet.getOriginalpics()).into(imageViewHolder.original_pic);
Picasso.get().load(displayDuet.getOriginalpics()).networkPolicy(NetworkPolicy.OFFLINE).placeholder(R.drawable.placeholder).into(imageViewHolder.original_pic, new Callback() {
@Override
public void onSuccess() {
}
@Override
public void onError(Exception e) {
Picasso.get().load(displayDuet.getOriginalpics()).placeholder(R.drawable.placeholder).into(imageViewHolder.original_pic);
}
});
// Glide.with(mContext).load(displayDuet.getPostimage()).into(imageViewHolder.post_pic);
Picasso.get().load(displayDuet.getPostimage()).networkPolicy(NetworkPolicy.OFFLINE).placeholder(R.drawable.placeholder).into(imageViewHolder.post_pic, new Callback() {
@Override
public void onSuccess() {
}
@Override
public void onError(Exception e) {
Picasso.get().load(displayDuet.getPostimage()).placeholder(R.drawable.placeholder).into(imageViewHolder.post_pic);
}
});
imageViewHolder.setiItemClickListener(new IItemClickListener() {
@Override
public void onItemClickListener(View view, int position) {
Intent intent = new Intent(mContext, DuetDisplayActivity.class);
intent.putExtra("postid", displayDuet.getPostid());
intent.putExtra("publisherid", displayDuet.getPublisher());
intent.putExtra("postduetid", displayDuet.getPostduetid());
mContext.startActivity(intent);
}
});
}
@Override
public int getItemCount() {
return mDisplayDuet.size();
}
public class ImageViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public ImageView post_pic, original_pic;
IItemClickListener iItemClickListener;
public void setiItemClickListener(IItemClickListener iItemClickListener) {
this.iItemClickListener = iItemClickListener;
}
public ImageViewHolder(@NonNull View itemView) {
super(itemView);
post_pic = itemView.findViewById(R.id.duet_pic_one);
original_pic = itemView.findViewById(R.id.duet_pic_two);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
iItemClickListener.onItemClickListener(view, getAdapterPosition());
}
}
}
和其他活动代码:
public class DuetDisplayActivity extends AppCompatActivity {
private String postid, publisher, postduetid;
private ImageView duet_close;
int position = 2;
private RecyclerView duet_show_recyclerView;
private DuetShowAdapter postAdapter;
private List<DisplayDuet> postList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_duet_display);
Intent intent = getIntent();
postid = intent.getStringExtra("postid");
publisher = intent.getStringExtra("publisherid");
postduetid = intent.getStringExtra("postduetid");
duet_close = findViewById(R.id.close);
duet_show_recyclerView = findViewById(R.id.duet_show_recyclerView);
duet_show_recyclerView.setHasFixedSize(true);
LinearLayoutManager mLayoutManager = new LinearLayoutManager(this);
duet_show_recyclerView.setLayoutManager(mLayoutManager);
postList = new ArrayList<>();
postAdapter = new DuetShowAdapter(this, postList);
duet_show_recyclerView.findViewHolderForAdapterPosition(position);
duet_show_recyclerView.setAdapter(postAdapter);
SnapHelper startSnapHelper = new PagerSnapHelper();
duet_show_recyclerView.setOnFlingListener(null);
startSnapHelper.attachToRecyclerView(duet_show_recyclerView);
duet_close.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
});
readPost();
}
private void readPost(){
DatabaseReference reference = FirebaseDatabase.getInstance().getReference("DuetPics").child(postid);
reference.keepSynced(true);
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
postList.clear();
for (DataSnapshot getsnapshot : dataSnapshot.getChildren()) {
for (DataSnapshot snapshot : getsnapshot.getChildren()) {
DisplayDuet displayDuet = snapshot.getValue(DisplayDuet.class);
postList.add(displayDuet);
}
Collections.reverse(postList);
postAdapter.notifyDataSetChanged();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
解决方案
我从您的问题中了解到,您希望将点击位置从 DisplayDuetAdapter 传递给您的 DuetDisplayActivity。
如果是这种情况,那么您可以按意图传递它。
所以像这样在 DisplayDuetAdapter 中传递按下的项目位置:
imageViewHolder.setiItemClickListener(new IItemClickListener() {
@Override
public void onItemClickListener(View view, int position) {
Intent intent = new Intent(mContext, DuetDisplayActivity.class);
//pass position like this
intent.putExtra("position", i);
intent.putExtra("postid", displayDuet.getPostid());
intent.putExtra("publisherid", displayDuet.getPublisher());
intent.putExtra("postduetid", displayDuet.getPostduetid());
mContext.startActivity(intent);
}
});
并像这样在 DuetDisplayActivity 中获得位置:
private int position;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_duet_display);
Intent intent = getIntent();
postid = intent.getStringExtra("postid");
publisher = intent.getStringExtra("publisherid");
postduetid = intent.getStringExtra("postduetid");
//get the passed position
position = intent.getIntExtra("position");
............
............
更新:
做这个:
//get the passed position
position = intent.getIntExtra("position",0);
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