Android 使用 View Holder

Question

我尝试使用 firebase 在我的应用中显示，但不返回图像或其他数据 请帮助我在没有任何错误后使用它，但现在我不使用此方法

public class PaylasAnaSayfa extends AppCompatActivity {

    private RecyclerView mBlogList;
    public DatabaseReference mDatabase;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_paylas_ana_sayfa);

        mDatabase= FirebaseDatabase.getInstance().getReference().child("Resimler");

        mBlogList= (RecyclerView) findViewById(R.id.resim_list);
        mBlogList.setHasFixedSize(true);
        mBlogList.setLayoutManager(new LinearLayoutManager(this));


        if (mDatabase==null){
            Toast.makeText(this, "veri tabanı hatası", Toast.LENGTH_SHORT).show();
        }else {
            FirebaseRecyclerAdapter<PaylasModel, PaylasHolder> adapter = new FirebaseRecyclerAdapter<PaylasModel, PaylasHolder>(
                    PaylasModel.class,
                    R.layout.resim_row,
                    PaylasHolder.class,
                    mDatabase
            ) {
                @Override
                protected void populateViewHolder(PaylasHolder viewHolder, PaylasModel model, int position) {
                    viewHolder.setImage(getApplicationContext(), model.getImgImage());
                    viewHolder.setBaslik(model.getImgBaslik());
                    viewHolder.setAciklama(model.getImgAciklama());
                    viewHolder.setKullanici(model.getImgKullaniciAdi());
                    viewHolder.setDers(model.getImgDers());
                }
            };

            mBlogList.setAdapter(adapter);

        }

    }


    private static class PaylasHolder extends RecyclerView.ViewHolder {
        View mView;
        public PaylasHolder(View itemView) {
            super(itemView);
            mView=itemView;
        }

        public void setBaslik(String baslik){
            TextView tBaslik= (TextView) mView.findViewById(R.id.row_img_baslik);
            tBaslik.setText(baslik);
        }

        public void setAciklama(String aciklama){
            TextView tAciklama= (TextView) mView.findViewById(R.id.row_img_aciklama);
            tAciklama.setText(aciklama);
        }

        public void setKullanici(String kullanici){
            TextView tKullanici= (TextView) mView.findViewById(R.id.row_img_kullanici);
            tKullanici.setText(kullanici);
        }
        public void setDers(String ders){
            TextView tDers= (TextView) mView.findViewById(R.id.row_img_ders);
            tDers.setText(ders);
        }

        public void setImage(final Context context, final String image){
            final ImageView tImage= (ImageView) mView.findViewById(R.id.row_img_image);
            Picasso.with(context).load(image).networkPolicy(NetworkPolicy.OFFLINE).into(tImage, new Callback() {
                @Override
                public void onSuccess() {

                }

                @Override
                public void onError() {
                    Picasso.with(context).load(image).into(tImage);
                }
            });
        }

    }

}

使用视图持有者不返回数据 方括号中的单词是替代文本，如果浏览器无法显示图像，则会显示该文本。请务必为屏幕阅读软件添加有意义的替代文字。

Answer 1

首先，您不需要在 ViewHolder 的方法中每次都初始化视图。RecyclerView 会重用视图池中的视图。

private static class PaylasHolder extends RecyclerView.ViewHolder {
    View mView;
    TextView tBaslik;
    public PaylasHolder(View itemView) {
        super(itemView);
        mView=itemView;
         tBaslik = mView.findViewById(R.id.row_img_baslik);
        //intialize all you view here once and for all. 
     }

    public void setBaslik(String baslik){
        tBaslik.setText(baslik);
    }

    public void setAciklama(String aciklama){
        tAciklama.setText(aciklama);
    }

    public void setKullanici(String kullanici){
        tKullanici.setText(kullanici);
    }
    public void setDers(String ders){
        tDers.setText(ders);
    }

    public void setImage(final Context context, final String image){          
     Picasso.with(context).load(image).networkPolicy(NetworkPolicy.OFFLINE).into(tImage, new Callback() {
            @Override
            public void onSuccess() {

            }

            @Override
            public void onError() {
                Picasso.with(context).load(image).into(tImage);
            }
        });
    }

}

如果您非常确定 recyclerview 的大小，则仅使用 setHasFixedSize(true) 否则它不会在向适配器添加数据时请求布局。