java - AbsListView$RecycleBin.addScrapView() 问题中的 SectionedAdapter ArrayIndexOutOfBoundsException？

Question

我有一个我正在使用的分段适配器，但是我正在尝试修改它，以便使用 if (section.adapter.getCount() > 0) 使这些部分在它们为空时不会出现。我有以下类(class):

abstract public class SectionedAdapter extends BaseAdapter {

abstract protected View getHeaderView(String caption, int index, View convertView, ViewGroup parent);

private List<Section> sections = new ArrayList<Section>(); 
private static int TYPE_SECTION_HEADER = 0; 

public SectionedAdapter() {
    super(); 
}

public void addSection(String caption, Adapter adapter) { 
    sections.add(new Section(caption, adapter)); 
}

public void clear() {
    sections.clear();
    notifyDataSetInvalidated();
}

@Override
public Object getItem(int position) { 

    for (Section section : this.sections) {
        if (section.adapter.getCount() > 0) {

            if (position == 0) {
                return section;
            }

            int size = section.adapter.getCount() + 1;

            if (position < size) {
                return section.adapter.getItem(position - 1);
            }

            position -= size; 
        }
    } 

    return null; 
}

@Override
public int getCount() {
    int total = 0; 
    for (Section section : this.sections) {
        if (section.adapter.getCount() > 0) {
            // Add Header and Section
            total += section.adapter.getCount() + 1;
        }
    }
    return total;
} 

@Override
public int getViewTypeCount() {
    int total = 1; // Add Header
    for (Section section : this.sections) {
        if (section.adapter.getCount() > 0) {
            // Add Sections
            total += section.adapter.getViewTypeCount();
        }
    } 
    return total;
} 

@Override
public int getItemViewType(int position) { 
    int typeOffset = TYPE_SECTION_HEADER + 1;

    for (Section section : this.sections) {
        if (section.adapter.getCount() > 0) {

            if (position == 0) {
                return TYPE_SECTION_HEADER;
            }

            int size = section.adapter.getCount() + 1;

            if (position < size) {
                return (typeOffset + section.adapter.getItemViewType(position - 1));
            }

            position -= size; 
            typeOffset += section.adapter.getViewTypeCount();
        }
    } 

    return Adapter.IGNORE_ITEM_VIEW_TYPE;
}

@Override
public boolean areAllItemsEnabled() { 
    return false; 
}

@Override
public boolean isEnabled(int position) { 
    return (getItemViewType(position) != TYPE_SECTION_HEADER); 
}

@Override
public View getView(int position, View convertView, ViewGroup parent) { 
    int sectionIndex = 0;
    for (Section section : this.sections) {
        if (section.adapter.getCount() > 0) {

            if (position == 0) {
                return getHeaderView(section.caption, sectionIndex, null, parent);
            }

            int size = section.adapter.getCount() + 1;

            if (position < size) {
                return section.adapter.getView(position - 1, null, parent);
            } 

            position -= size;
            sectionIndex++;
        }
    }
    return null; 
} 

@Override
public long getItemId(int position) { 
    return position; 
}

class Section { 
    String caption; 
    Adapter adapter; 

    Section(String caption, Adapter adapter) { 
        this.caption = caption; 
        this.adapter = adapter; 
    } 
}

这是有效的，但有时它会因错误而崩溃AbsListView$RecycleBin.addScrapView() 中的 ArrayIndexOutOfBoundsException

java.lang.ArrayIndexOutOfBoundsException
at android.widget.AbsListView$RecycleBin.addScrapView(AbsListView.java:4186)
at android.widget.ListView.layoutChildren(ListView.java:1572)
at android.widget.AbsListView.onLayout(AbsListView.java:1172)
at android.view.View.layout(View.java:7037)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1249)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1125)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1042)
at android.view.View.layout(View.java:7037)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at android.view.View.layout(View.java:7037)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at android.view.View.layout(View.java:7037)
at android.view.ViewRoot.performTraversals(ViewRoot.java:1054)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1736)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:143)
at android.app.ActivityThread.main(ActivityThread.java:4701)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)

我知道这个错误很可能与 getViewTypeCount() 或 getItemViewType(int position) 有关，但我无法弄清楚我哪里出错了(由于其他 StackOverflow 搜索)。异常不会可靠地发生，所以我不知道为什么会发生这种情况。我在这里遗漏了什么吗？

Answer 1

如果我没记错的话，您的目标是在该部分为空时不显示该部分。我不认为你在这里申请的条件会给你你想要的结果。

因此删除您在 SectionedAdapter 中设置的条件。 getHeaderView 是这里的抽象方法。但是实现是在其他一些类中编写的，您必须像我一样进行修改。

SectionedAdapter adapter = new SectionedAdapter() {
        protected View getHeaderView(String caption, int index, View convertView, ViewGroup parent) {
            TextView result = (TextView)convertView;

            if (convertView == null) {
                result=(TextView)getLayoutInflater().inflate(R.layout.header, null);
            }
            if(caption != null) {
                result.setText(caption);
            } else {
                result.setVisibility(View.GONE);
            }

            return(result);
        }
    };

如果您不想插入任何部分，则在 addSelection() 方法中传递 null 而不是部分名称。

请看我修改后的代码。尝试运行 SectionedDemo 类

// SectionedDemo class
//----------------------
import android.app.ListActivity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class SectionedDemo extends ListActivity {
    private static String[] items={ "lorem", "ipsum", "dolor", "sit", "amet", "consectetuer", "adipiscing", 
                                    "elit", "morbi", "vel", "ligula", "vitae", "arcu", "aliquet", "mollis", 
                                    "etiam", "vel", "erat", "placerat", "ante", "porttitor", "sodales", 
                                    "pellentesque", "augue", "purus"};

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main1);

        adapter.addSection(null, new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, items));

        List<String> list = Arrays.asList(items);
        Collections.shuffle(list);
        adapter.addSection(null, new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list));

        list = Arrays.asList(items);
        Collections.shuffle(list);
        adapter.addSection(null, new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list));

        setListAdapter(adapter);
    }

    SectionedAdapter adapter = new SectionedAdapter() {
        protected View getHeaderView(String caption, int index, View convertView, ViewGroup parent) {
            TextView result=(TextView)convertView;

            if (convertView==null) { 
                result=(TextView)getLayoutInflater() .inflate(R.layout.header, null);
            }
            if(caption != null) {
                result.setText(caption);
            } else {
                result.setVisibility(View.GONE);
            }

            return(result);
        }
    };
}

下面是SectionedAdapter类

//SectionedAdapter class
//-------------------------
import android.view.View;
import android.view.ViewGroup;
import android.widget.Adapter;
import android.widget.BaseAdapter;
import java.util.ArrayList;
import java.util.List;

abstract public class SectionedAdapter extends BaseAdapter {
    abstract protected View getHeaderView(String caption, int index, View convertView, ViewGroup parent);

    private List<Section> sections=new ArrayList<Section>();
    private static int TYPE_SECTION_HEADER=0;

    public SectionedAdapter() {
        super();
    }

    public void addSection(String caption, Adapter adapter) {
        sections.add(new Section(caption, adapter));
    }

    public Object getItem(int position) {
        for (Section section : this.sections) {
            if (position==0) {
                return(section);
            }

            int size=section.adapter.getCount()+1;

            if (position<size) {
                return(section.adapter.getItem(position-1));
            }

            position-=size;
        }

        return(null);
    }

    public int getCount() {
        int total = 0;

        for (Section section : this.sections) {
            total += section.adapter.getCount()+1; // add one for header
        }

        return(total);
    }

    public int getViewTypeCount() {
        int total = 1;  // one for the header, plus those from sections

        for (Section section : this.sections) {
            total += section.adapter.getViewTypeCount();
        }

        return(total);
    }

    public int getItemViewType(int position) {
        int typeOffset=TYPE_SECTION_HEADER+1;   // start counting from here

        for (Section section : this.sections) {
            if (position==0) {
                return(TYPE_SECTION_HEADER);
            }

            int size=section.adapter.getCount()+1;

            if (position<size) {
                return(typeOffset+section.adapter.getItemViewType(position-1));
            }

            position-=size;
            typeOffset+=section.adapter.getViewTypeCount();
        }

        return(-1);
    }

    public boolean areAllItemsSelectable() {
        return(false);
    }

    public boolean isEnabled(int position) {
        return(getItemViewType(position)!=TYPE_SECTION_HEADER);
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        int sectionIndex=0;

        for (Section section : this.sections) {

            if (position==0) {
                return(getHeaderView(section.caption, sectionIndex, convertView, parent));
            }

            int size=section.adapter.getCount()+1;

            if (position<size) {
                return(section.adapter.getView(position-1, convertView, parent));
            }

            position-=size;
            sectionIndex++;
        }

        return(null);
    }

    public long getItemId(int position) {
        return(position);
    }

    class Section {
        String caption;
        Adapter adapter;

        Section(String caption, Adapter adapter) {
            this.caption=caption;
            this.adapter=adapter;
        }
    }
}