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我正在制作一个应用程序，RecyclerView当滚动到底部时，它会显示一些漂亮的女孩。而且我遇到了一些问题，您可以在此处的视频链接中看到它。

或者：

I. 添加更多项目时，它只显示一列，而不是定义的所有 3 列。

二、向上滚动时，所有子视图都移动得非常快，然后RecyclerView将我带到顶部并跳过其中的所有项目。示例：当前项目为 100 并向上滚动，几毫秒后您站在列表顶部。

我的项目有：

  1. build.grade: compile 'com.android.support:recyclerview-v7:23.4.0': 我不想更新RecyclerView到 24 因为 JDK 版本。

  2. MainActivity 扩展了 AppCompatActivity：

    public class MainActivity extends AppCompatActivity {
private RelativeLayout rootView;
private RecyclerView mRecyclerView;
private StaggeredGridLayoutManager mLayoutManager;
private ImagesAdapter mAdapter;
private Handler mHandler;

private int currentOffset;

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

    currentOffset = 0;
    loading = true;
    mHandler = new Handler(getMainLooper());
    initRetrofit();
    initWidget();

    fetchingData(true);
}

private void initRetrofit() {
    Gson gson = new GsonBuilder().disableHtmlEscaping().create();
    OkHttpClient.Builder builderHttpClient = new OkHttpClient.Builder();
    //builderHttpClient.interceptors().add(new LoggingInterceptor());
    OkHttpClient client = builderHttpClient.build();

    NetworkManager.init(new Retrofit.Builder().baseUrl(APIConfig.BASE_URL).addConverterFactory(new ToStringConverterFactory()).addConverterFactory(GsonConverterFactory.create(gson)).client(client).build());
}

private void initWidget() {
    mRecyclerView = (RecyclerView) findViewById(R.id.rv_main);
    mLayoutManager = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);
    mAdapter = new ImagesAdapter(this, new ArrayList<PhotoItemModel>());

    mRecyclerView.setLayoutManager(mLayoutManager);
    mRecyclerView.addItemDecoration(new SpacesItemDecoration(15));
    mRecyclerView.setAdapter(mAdapter);

    mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            if (dy > 0) //check for scroll down
            {
                visibleItemCount = mLayoutManager.getChildCount();
                totalItemCount = mLayoutManager.getItemCount();

                int[] items = mLayoutManager.findFirstCompletelyVisibleItemPositions(null);
                if (items.length > 0) {
                    pastVisibleItems = items[0];
                }

                if (loading) {
                    if ((visibleItemCount + pastVisibleItems) >= totalItemCount) {
                        loading = false;
                        fetchingData();
                    }
                }
            }
        }
    });
}

private void fetchingData() {
    currentOffset = mAdapter.getItemCount();
    mHandler.postDelayed(new Runnable() {
        @Override
        public void run() {
            NetworkManager.getPhotoByOffset(currentOffset, new Callback<GetPhotoResponse>() {
                @Override
                public void onResponse(Call<GetPhotoResponse> call, retrofit2.Response<GetPhotoResponse> response) {
                    if (null != response && null != response.body()) {
                        ResponseModel responseModel = response.body().getResponseModel();
                        List<PostItemModel> postItemModels = responseModel.getPostItemModels();
                        List<PhotoItemModel> photoItemModels = new ArrayList<>();
                        for (PostItemModel postItemModel : postItemModels) {
                            photoItemModels.addAll(postItemModel.getPhotos());
                        }
                        mAdapter.insertMoreItems(photoItemModels);
                        loading = true;
                    } else {
                        loading = true;
                        fetchingData();
                    }
                }

                @Override
                public void onFailure(Call<GetPhotoResponse> call, Throwable t) {
                    t.printStackTrace();
                    loading = true;
                    fetchingData();
                }
            });
        }
    }, 5000);
}
}

  3. 适配器：

    public class ImagesAdapter extends RecyclerView.Adapter<VHImage> {
private MainActivity mainActivity;
private List<PhotoItemModel> photoItemModels;

public ImagesAdapter(MainActivity mainActivity, ArrayList<PhotoItemModel> photoItemModels) {
    this.mainActivity = mainActivity;
    this.photoItemModels = photoItemModels;
}

public List<PhotoItemModel> getPhotoItemModels() {
    return photoItemModels;
}

@Override
public VHImage onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_image, parent, false);
    return new VHImage(mainActivity, view);
}

@Override
public void onBindViewHolder(VHImage holder, int position) {
    holder.bindData(photoItemModels.get(position));
}

@Override
public int getItemCount() {
    return photoItemModels.size();
}

public void insertMoreItems(List<PhotoItemModel> morePhotoItemModels) {
    int oldSize = photoItemModels.size();
    photoItemModels.addAll(morePhotoItemModels);
    notifyItemRangeInserted(oldSize, morePhotoItemModels.size());
}
}

  4. 视图持有者

    public class VHImage extends RecyclerView.ViewHolder implements View.OnClickListener {
private MainActivity mainActivity;
private ImageView ivImage;
private View div1, div2;
private PhotoItemModel photoItemModel;

public VHImage(MainActivity mainActivity, View itemView) {
    super(itemView);
    this.mainActivity = mainActivity;
    ivImage = (ImageView) itemView.findViewById(R.id.iv_image);
    div1 = itemView.findViewById(R.id.v_div_1);
    div2 = itemView.findViewById(R.id.v_div_2);
    ivImage.setOnClickListener(this);
}

public void bindData(PhotoItemModel photoItemModel) {
    this.photoItemModel = photoItemModel;
    Glide.with(mainActivity.getApplicationContext())
            .load(photoItemModel.getAltSizesList().get(2).getUrl())
            .diskCacheStrategy(DiskCacheStrategy.RESULT)
            .listener(new RequestListener<String, GlideDrawable>() {
                @Override
                public boolean onException(Exception e, String model, Target<GlideDrawable> target, boolean isFirstResource) {
                    div1.setVisibility(View.INVISIBLE);
                    div2.setVisibility(View.INVISIBLE);
                    return false;
                }

                @Override
                public boolean onResourceReady(GlideDrawable resource, String model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
                    div1.setVisibility(View.VISIBLE);
                    div2.setVisibility(View.VISIBLE);
                    return false;
                }
            })
            .into(ivImage);
}

@Override
public void onClick(View view) {
    mainActivity.onImageClick(view, ((ImageView) view).getDrawable(), photoItemModel);
}
}

  5. 活动布局

    <android.support.v7.widget.RecyclerView
    android:id="@+id/rv_main"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="0.5dp"
    android:visibility="invisible" />

<ImageView
    android:id="@+id/iv_full_screen"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:adjustViewBounds="true"
    android:scaleType="fitCenter"
    android:visibility="invisible" />


<ImageView
    android:id="@+id/iv_splash1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:adjustViewBounds="true"
    android:scaleType="fitCenter"
    android:visibility="gone" />

<ImageView
    android:id="@+id/iv_splash2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:adjustViewBounds="true"
    android:scaleType="fitCenter"
    android:visibility="gone" />

<ProgressBar
    android:id="@+id/pb_loading"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="200dp"
    android:layout_height="wrap_content"
    android:layout_below="@+id/iv_splash1"
    android:layout_centerHorizontal="true"
    android:layout_gravity="bottom"
    android:layout_marginBottom="3dp"
    android:layout_marginTop="20dp"
    android:indeterminate="true"
    android:max="1000"
    android:progressDrawable="@drawable/progress_drawable" />

  6. 项目布局

    <View
    android:id="@+id/v_div_1"
    android:layout_width="match_parent"
    android:layout_height="1dp"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    android:background="#000000"
    android:visibility="invisible" />

<View
    android:id="@+id/v_div_2"
    android:layout_width="match_parent"
    android:layout_height="1dp"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:layout_marginTop="0.5dp"
    android:background="#000000"
    android:visibility="invisible" />

<ImageView
    android:id="@+id/iv_image"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="0.5dp"
    android:adjustViewBounds="true" />

4

1 回答 1

0

在下载图像之前，您无法找到它的大小，除非您从网络服务发送图像大小并ImageView在显示之前设置您的高度。

例如，您的网络服务响应可能是这样的：

{
    "ImageLink" = "http://www.example.com/example.jpg"
    "ImageWidth" = 1024
    "ImageHeight" = 768
}

然后ImageView像这样设置你的尺寸：

imageview.getLayoutParams().height = imageview.getWidth() * (ImageHeight/ImageWidth);

为了获得更好的性能，ImageView请在将布局大小添加到RecyclerView.

于 2016-12-13T05:03:24.953 回答