Question

我有一个适配器，应该从Firebase存储中获取每个用户的个人资料图片并将其设置在ImageView中，但是发生的是，每次更新时，它都会为所有图像视图更改相同的个人资料图片。（因此，它将在所有图像视图上显示最后获取的图片）。这是获取和设置图片的代码部分：

@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
    myHolder = holder;   

    StorageReference ref = storageRef.child("profilePictures").child(mDataset.get(position));

    final long ONE_MEGABYTE = 1024 * 1024;
    ref.getBytes(ONE_MEGABYTE).addOnSuccessListener(new OnSuccessListener<byte[]>() {
        @Override
        public void onSuccess(byte[] bytes) {

            Log.d("Tag", "Success");
            bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);

        }
    }).addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception exception) {
            // Handle any errors
            Log.d("Tag", "Failure");
        }
    });

    myHolder.singleItemImage.setImageBitmap(bitmap);
}

布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">


    <ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:layout_marginBottom="16dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="1.0"
        app:srcCompat="@drawable/ic_launcher_background" />


    <TextView
        android:id="@+id/text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="Test"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/icon" />

</android.support.constraint.ConstraintLayout>

mUpdatesReference = FirebaseDatabase.getInstance（）。getReference（“ timeUpdates”）; mAdapter =新的MyAdapter（myDataset）; ValueEventListener监听程序=新的ValueEventListener（）{

        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            boolean isChanged = false;

            for(DataSnapshot datas: dataSnapshot.getChildren()){
               if (time < 180 )){                        
                    if (!myDataset.contains(datas.getKey().toString())){
                        myDataset.add(datas.getKey().toString());
                        isChanged = true;
                    }
                } else {

                    myDataset.remove(datas.getKey().toString());
                    isChanged = true;


                }
                if (isChanged) {
                    mAdapter.notifyDataSetChanged();
                }
}
        mUpdatesReference.addValueEventListener(listener);

    mRecyclerView.setAdapter(mAdapter);

Answer 1

因为获得位图并将其设置为方法之外的位置，并且不释放该位图，所以它将为所有用户设置。只需将您的方法更改为此：

    @Override
        public void onBindViewHolder(MyViewHolder holder, int position) {
            myHolder = holder;   

            StorageReference ref = storageRef.child("profilePictures").child(mDataset.get(position));

            final long ONE_MEGABYTE = 1024 * 1024;
            ref.getBytes(ONE_MEGABYTE).addOnSuccessListener(new OnSuccessListener<byte[]>() {
                @Override
                public void onSuccess(byte[] bytes) {

                    Log.d("Tag", "Success");
                    bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
                    if(bitmap!=null)
                    myHolder.singleItemImage.setImageBitmap(bitmap);
                    else myHolder.singleItemImage.setImageResource(R.drawable.YourPlaceholder); 

                }
            }).addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception exception) {
                    // Handle any errors
                    Log.d("Tag", "Failure");
                   myHolder.singleItemImage.setImageResource(R.drawable.YourPlaceholder); 
                }
            });


        }

Answer 2

首先使用位图参考更新模型

void downloadImage(int rowindex){
StorageReference ref = storageRef.child("profilePictures").child(mDataset.get(rowindex).getId());

    final long ONE_MEGABYTE = 1024 * 1024;
    ref.getBytes(ONE_MEGABYTE).addOnSuccessListener(new OnSuccessListener<byte[]>() {
        @Override
        public void onSuccess(byte[] bytes) {

            Log.d("Tag", "Success");
            bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
            mDataset.get(rowindex).setDownloadedBitmap(bitmap);
            notifyDataSetChanged ();

        }

在onBindViewHolder（）中添加

    public void onBindViewHolder(MyViewHolder holder, int position) {
        myHolder = holder; 

     Bitmap currentBitmap=mDataset.get(rowindex).getDownloadedBitmap();
   if(currentBitmap!=null){
     myHolder.singleItemImage.setImageBitmap(currentBitmap);
     }else{
     downloadImage(position);
     myHolder.singleItemImage.setImageResource(R.drawable.default);
 }

}

ProfilePictureItem.java

   public class ProfilePictureItem{

    private String key;
    private Bitmap downloadedBitmap;

    public setKey(String key){
     this.key=key;
    }
      public getKey(){
      return key;
     }
     public setDownloadedBitmap(Bitmap downloadedBitmap){
      this.downloadedBitmap=downloadedBitmap;
      }
      public getDownloadedBitmap(){
      return downloadedBitmap;
      }

      }

RecyclerView的适配器显示相同的图片，而不显示不同的图片

2 个答案: