Question

我希望我的listview在滚动到结尾后重复所有行，依此类推。这称为无限或循环，您可以找到实现它的方法，但这些似乎都不适用于我的适配器。我试过这种方法：How to create a closed (circular) ListView?但是当我把

时我的应用程序崩溃了

    @Override
    public int getCount()
    {
        return Integer.MAX_VALUE;
    }

此外，getItem doesent似乎＆＃34;沿着＆＃34;使用我的适配器

    @Override
    public T getItem(int position) 
    {
        return objects[position % objects.length];
    }

有没有办法为我的适配器实现类似的东西？这是代码：

    public class EntryAdapter extends ArrayAdapter<Item> {
private ArrayList<Item> items;
private Context fontcontext;
private LayoutInflater vi;


public EntryAdapter(Context context, ArrayList<Item> items) {
    super(context,0, items);
    fontcontext = context;
    this.items = items;
    vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;

    final Item i = items.get(position);
    if (i != null) {
       if(i.isSection()){
            SectionItem si = (SectionItem)i;
            v = vi.inflate(R.layout.list_item_section, null);

            v.setOnClickListener(null);
            v.setOnLongClickListener(null);
            v.setLongClickable(false);

            final TextView sectionView = (TextView) v.findViewById(R.id.list_item_section_text);
            sectionView.setText(si.getTitle());
            Typeface faceT = Typeface.createFromAsset(fontcontext.getAssets(),"fonts/Walkwayrounded.ttf");
            sectionView.setTypeface(faceT);
            final TextView conditionView = (TextView) v.findViewById(R.id.textViewn);
            conditionView.setText(si.getCondition());
            Typeface faceC = Typeface.createFromAsset(fontcontext.getAssets(),"fonts/Walkwayrounded.ttf");
            conditionView.setTypeface(faceC);

        }else{
            EntryItem ei = (EntryItem)i;
            v = vi.inflate(R.layout.list_item_entry, null);
            final TextView title = (TextView)v.findViewById(R.id.list_item_entry_title);
            final TextView subtitle = (TextView)v.findViewById(R.id.list_item_entry_summary);


            if (title != null) 
                title.setText(ei.title);
            if(subtitle != null)
                subtitle.setText(ei.subtitle);
        }
    }
    return v;
}

    }

任何解决问题的方法都将受到赞赏！

Answer 1

看起来您的主要问题是如何引用这些项目。你不能使用items.get(position)因为位置会溢出。尝试将这些方法添加到适配器：

@Override
public int getCount() {
    return Integer.MAX_VALUE;
}

@Override
public Item getItem(int position) {
    return items.get(position % items.size());
}

并替换

final Item i = items.get(position);

带

final Item i = getItem(position);

Answer 2

首先，您应该使用更有效的方式来绘制列表项。

Android Developer Resources网站提供了一个可以下载的“API Demos”SDK。有大量的样本和配方可用于与OS一起使用的不同方法。一个是专门为处理包含数千个条目或内存占用图像的列表而创建的 - 称为EfficientAdapter，它扩展了BaseAdapter类，允许您在View期间回收getView src.com.example.apis.view回调而不是膨胀新的xml布局。

我在/* * Copyright (C) 2008 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.example.android.apis.view; import android.app.ListActivity; import android.content.Context; import android.os.Bundle; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.TextView; import android.widget.ImageView; import android.graphics.BitmapFactory; import android.graphics.Bitmap; import com.example.android.apis.R; /** * Demonstrates how to write an efficient list adapter. The adapter used in this example binds * to an ImageView and to a TextView for each row in the list. * * To work efficiently the adapter implemented here uses two techniques: * - It reuses the convertView passed to getView() to avoid inflating View when it is not necessary * - It uses the ViewHolder pattern to avoid calling findViewById() when it is not necessary * * The ViewHolder pattern consists in storing a data structure in the tag of the view returned by * getView(). This data structures contains references to the views we want to bind data to, thus * avoiding calls to findViewById() every time getView() is invoked. */ public class List14 extends ListActivity { private static class EfficientAdapter extends BaseAdapter { private LayoutInflater mInflater; private Bitmap mIcon1; private Bitmap mIcon2; public EfficientAdapter(Context context) { // Cache the LayoutInflate to avoid asking for a new one each time. mInflater = LayoutInflater.from(context); // Icons bound to the rows. mIcon1 = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon48x48_1); mIcon2 = BitmapFactory.decodeResource(context.getResources(), R.drawable.icon48x48_2); } /** * The number of items in the list is determined by the number of speeches * in our array. * * @see android.widget.ListAdapter#getCount() */ public int getCount() { return DATA.length; } /** * Since the data comes from an array, just returning the index is * sufficent to get at the data. If we were using a more complex data * structure, we would return whatever object represents one row in the * list. * * @see android.widget.ListAdapter#getItem(int) */ public Object getItem(int position) { return position; } /** * Use the array index as a unique id. * * @see android.widget.ListAdapter#getItemId(int) */ public long getItemId(int position) { return position; } /** * Make a view to hold each row. * * @see android.widget.ListAdapter#getView(int, android.view.View, * android.view.ViewGroup) */ public View getView(int position, View convertView, ViewGroup parent) { // A ViewHolder keeps references to children views to avoid unneccessary calls // to findViewById() on each row. ViewHolder holder; // When convertView is not null, we can reuse it directly, there is no need // to reinflate it. We only inflate a new View when the convertView supplied // by ListView is null. if (convertView == null) { convertView = mInflater.inflate(R.layout.list_item_icon_text, null); // Creates a ViewHolder and store references to the two children views // we want to bind data to. holder = new ViewHolder(); holder.text = (TextView) convertView.findViewById(R.id.text); holder.icon = (ImageView) convertView.findViewById(R.id.icon); convertView.setTag(holder); } else { // Get the ViewHolder back to get fast access to the TextView // and the ImageView. holder = (ViewHolder) convertView.getTag(); } // Bind the data efficiently with the holder. holder.text.setText(DATA[position]); holder.icon.setImageBitmap((position & 1) == 1 ? mIcon1 : mIcon2); return convertView; } static class ViewHolder { TextView text; ImageView icon; } } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setListAdapter(new EfficientAdapter(this)); } private static final String[] DATA = Cheeses.sCheeseStrings; }

下找到了它

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ArrayAdapter的循环（或无限）列表视图

2 个答案: