Android Gallery 在使用 DiscLru Cache 和 Volley 时滚动速度很慢

Question

我已经实现了带有Google I\O凌空抽射，凌空演示的图库视图，并成功下载图像并进行缓存。

首先，当我使用 LruCache 进行缓存时，它非常好，图库滚动很好。但是LruCache没有保持16MB的内存，而是只缓存4MB。我想缓存高达16MB。

所以我转而使用DiscLruCache代替LruCache。它按照我想要的方式进行缓存（16MB）。但问题是图库视图滚动非常慢，并且在下载和完成所有缓存（16MB）后不流畅。

这是我的代码。

    package com.technotalkative.volleyimageloading;
import java.util.ArrayList;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONObject;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Display;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.view.ViewGroup.MarginLayoutParams;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.TextView;
import com.android.volley.toolbox.NetworkImageView;
public class SimpleViewFrag extends Fragment {
    public static final String TAG = SimpleViewFrag.class.getSimpleName();
    private Gallery mGallery;
    private List<MyCataLogData> simpleViewList = new ArrayList<MyCataLogData>();
    MainActivity mainActivity;
    private LayoutInflater inflater;
    private int height;
    private int width;
    private int mItemWidth;
    private int mItemHeight;
    private SimpleViewAdapter mAdapter;
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        mainActivity = (MainActivity) activity;
    }
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Display display = getActivity().getWindowManager().getDefaultDisplay();
        height = display.getHeight();
        width = display.getWidth();
        mItemWidth = (int) (width / 1.7f);
        mItemHeight = (int) (height / 3f);
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        this.inflater = inflater;
        View v = null;
        v = inflater.inflate(R.layout.simple_view, container, false);

//      String s = getArguments().getString(UCConstants.CATALOG_CONTENT_KEY);
        mGallery = (Gallery) v.findViewById(R.id.simpleViewGalleruy);
        mAdapter = new SimpleViewAdapter();
        mGallery.setAdapter(mAdapter);
//      mGallery.setSelection(1);
        DisplayMetrics metrics = new DisplayMetrics();
        getActivity().getWindowManager().getDefaultDisplay().getMetrics(metrics);
        // set gallery to left side
        MarginLayoutParams mlp = (MarginLayoutParams) mGallery.getLayoutParams();
        mlp.setMargins(-((int) (metrics.widthPixels / 3.8f)), mlp.topMargin,
                    mlp.rightMargin, mlp.bottomMargin);
        parseJsonForCataLog();

        mGallery.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int position,
                    long arg3) {
                Log.e(TAG, "position: ====="+position);
            }
        });
        return v;
    }
    public class SimpleViewAdapter extends BaseAdapter {
        @Override
        public int getCount() {
            return simpleViewList.size();
        }
        @Override
        public Object getItem(int position) {
            return simpleViewList.get(position);
        }
        @Override
        public long getItemId(int position) {
            return position;
        }
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            NetworkImageView networkImageView = null;
            TextView tvTitle = null;
            TextView tvText = null;
            View childView = null;

            if (convertView == null) {
                childView = inflater.inflate(R.layout.simple_view_content_item, null);
            } else {
                childView = convertView;
            }
            if (childView != null) {
                networkImageView = (NetworkImageView) childView
                        .findViewById(R.id.networkImageView);
                networkImageView.getLayoutParams().width = mItemWidth;
                networkImageView.getLayoutParams().height = LayoutParams.MATCH_PARENT;
                //getting an object for gallery item
                MyCataLogData cld = simpleViewList.get(position);
                if (networkImageView != null) {
                         networkImageView
                            .setImageUrl(cld.getSimpleImageUrl(), ImageCacheManager.getInstance().getImageLoader());
                }
                tvTitle = (TextView) childView.findViewById(R.id.title);
                if (tvTitle != null) {
                    tvTitle.setText(cld.getSimpleTitle());
                }
                tvText = (TextView) childView.findViewById(R.id.text);
                if (tvText != null) {
                    tvText.setText(cld.getSimpleText());
                }
            }
            return childView;
        }
    }
    protected void parseJsonForCataLog() {
        try {
            String jsonObjectString = getArguments().getString("JSONObject");
            JSONObject rootResponce = new JSONObject(jsonObjectString);
            Log.e(TAG, "rootResponce: " + rootResponce);
            JSONArray simpleArray = rootResponce.optJSONArray("SIMPLE");
            if(simpleArray == null)
                return;
            for (int i = 0; i < simpleArray.length(); i++) {
                JSONObject childMenuObject = simpleArray.getJSONObject(i);
                String textSimple = childMenuObject.optString("text");
                String titleSimple = childMenuObject.optString("title");
                String imageUrlSimple = childMenuObject.optString("imageUrl");
                MyCataLogData mcld = new MyCataLogData(null ,textSimple, titleSimple, imageUrlSimple);
                simpleViewList.add(mcld);
//              Log.e(TAG, "" + childMenuObject);
            }
            mAdapter.notifyDataSetChanged();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Answer 1

我在 ListView 上遇到了同样的问题，但我在谷歌的 iosched 应用程序中找到了解决方案。您可以尝试应用以下内容，但我建议使用水平列表视图，例如Lucas Rocha的TwoWayView。这个解决方案可以应用于它，只需实现TwoWayView.OnScrollListener

即可

添加 AbsListView onscroll 侦听器方法，并在快速/投掷滚动时停止凌空抽射

public class SimpleViewFrag extensions Fragment implements AbsListView.OnScrollListener {

    ListView mListView;
    mListView.setOnScrollListener(this);
@Override
public void onScrollStateChanged( AbsListView view, int scrollState ) {
    // Pause disk cache access to ensure smoother scrolling
    if (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_FLING) {
        VolleyHelper.getImageLoader().getRequestQueue().stop();
    } else {
        VolleyHelper.getImageLoader().getRequestQueue().start();
    }
}
@Override
public void onScroll( AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount ) {
}

Answer 2

如果我理解正确（在您的示例中找不到ImageLoader初始化），那么当您应该提供内存缓存时，您似乎正在为 Volley ImageLoader构造函数提供磁盘缓存。

如果您的内存缓存大小太有限，您应该编辑代码以使其更大，或者找到/创建 ImageCache 接口的新实现，以您想要的方式工作。

无论您选择什么 - 不要在需要内存缓存的地方使用磁盘缓存。