绕过过滤中不更新 ListView Android 的 bug

Question

这是代码，我使用了自定义适配器，并应用了 Filter 方法，现在 ListView 在输入退格键时不会更新，当从项目活动切换回来时。我读到它是过滤器中的一个错误，但我如何绕过它，我知道已经实现了我想要的这种设置的应用程序。

public class IndexPageActivity extends Activity implements OnItemClickListener{ 
    ListView listView;
    EditText editTextB;
    PagesAdapter adapter1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.pageList);
        editTextB = (EditText) findViewById(R.id.searchB);
        adapter1 = new PagesAdapter(this);
        listView.setAdapter(adapter1);
        adapter1.notifyDataSetChanged();
        listView.setOnItemClickListener(this);

        editTextB.addTextChangedListener(new TextWatcher() {
            @Override
            public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                IndexPageActivity.this.adapter1.getFilter().filter(cs.toString());
                adapter1.notifyDataSetChanged();
            }

            @Override
            public void beforeTextChanged(CharSequence arg0, int arg1,
                        int arg2, int arg3) { }

            @Override
            public void afterTextChanged(Editable arg0) { }
        });
    }

    @Override
    public void onItemClick(AdapterView<?> arg0, View v, int position, long arg3) {
        Intent i;
        String name = adapter1.getItem(position);
        Log.d("id", name);

        if (name.equals("Item1"))
        {
            i = new Intent(this, anActivity.class);
            startActivity(i);
        }
        else if (name.equals("Item2"))
        {
            i = new Intent(this, anActivity2.class);
            startActivity(i);
        }
    }
}

class SingleRow {
    String pagedata;
    SingleRow(String pagedata){
        this.pagedata=pagedata;
    }
}
class PagesAdapter extends BaseAdapter implements Filterable{
    ArrayList<String> pagelist;
    List<String> arrayList;
    Context context;
    String [] pagedatas;

    PagesAdapter(Context c){
        context=c;
        pagelist = new ArrayList<String>();
        Resources res = c.getResources();
        pagedatas = res.getStringArray(R.array.pages_data);
        for (int i=0;i<463;i++){
            pagelist.add(pagedatas[i]);
        }
    }
    @Override
    public int getCount() {
        return pagelist.size();
    }

    @Override
    public String getItem(int i) {
        return pagelist.get(i);
    }

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

    @Override
    public View getView(int i, View view, ViewGroup viewG) {
        LayoutInflater inflater=(LayoutInflater)             context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View row=inflater.inflate(R.layout.single_row,viewG,false);
        TextView pagetitle = (TextView) row.findViewById(R.id.textViewRow);

        String temp=pagelist.get(i);

        pagetitle.setText(temp);
        return row;
    }

    public class filter_here extends Filter{
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            FilterResults Result = new FilterResults();
            // if constraint is empty return the original names
            if(constraint.length() == 0 ){
                Result.values = pagelist;
                Result.count = pagelist.size();
                return Result;
            }

            ArrayList<String> Filtered_Names = new ArrayList<String>();
            String filterString = constraint.toString().toLowerCase();
            String filterableString;

            for(int i = 0; i<pagelist.size(); i++){
                filterableString = pagelist.get(i);
                if(filterableString.toLowerCase().contains(filterString)){
                    Filtered_Names.add(filterableString);
                }
            }
            Result.values = Filtered_Names;
            Result.count = Filtered_Names.size();

            return Result;
        }

        @Override
        protected void publishResults(CharSequence constraint,FilterResults results) {
            pagelist = (ArrayList<String>) results.values;
            notifyDataSetChanged();
        }
    }

    @Override
    public Filter getFilter() {
        return new filter_here();
    }
}

Answer 1

1) 退格过滤

在您的publishResults 中，您正在修改您的pagelist，因此如果您按退格键并再次过滤，pagelist 仅包含原始pagelist 条目的一小部分：

因此，您需要保留原始数据的副本！比如：

List<String> allData;

PagesAdapter(Context c) {
    ...
    allData = pagelist;
    ...
}

在您的过滤方法中，使用 allData 对象：

for (int i = 0; i < allData.size(); i++) {
    filterableString = allData.get(i);
    if (filterableString.toLowerCase().contains(filterString)) {
        Filtered_Names.add(filterableString);
    }
}

以及您将数据重置为原始数据的位置：

// if constraint is empty return the original names
if (constraint.length() == 0) {
    Result.values = allData;
    Result.count = allData.size();
    return Result;
}

2) 从另一个活动返回后清除过滤器：

这可以在 onResume 中完成...就个人而言，我会清除 editText 中的文本以重置过滤器，如下所示：

@Override
protected void onResume() {
    if (editTextB != null) {
        editTextB.setText("");
    }
    super.onResume();
}

Answer 2

终于找到了退格的bug，你的过滤函数有一些错误，返回的是一个ArrayList，而不是保存变量的List，最终代码应该是：

public class IndexPageActivity extends Activity implements OnItemClickListener{ 
ListView listView;
EditText editTextB;
PagesAdapter adapter1;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.pageList);
        editTextB = (EditText) findViewById(R.id.searchB);
        adapter1 = new PagesAdapter(this);
        listView.setAdapter(adapter1);
        adapter1.notifyDataSetChanged();
        listView.setOnItemClickListener(this);

        editTextB.addTextChangedListener(new TextWatcher() {

            @Override
            public void onTextChanged(CharSequence cs, int arg1, int arg2,
                    int arg3) {
                // When user changed the Text
                IndexPageActivity.this.adapter1.getFilter().filter(cs.toString());
                adapter1.notifyDataSetChanged();
            }

            @Override
            public void beforeTextChanged(CharSequence arg0, int arg1,
                    int arg2, int arg3) {
                // TODO Auto-generated method stub

            }

            @Override
            public void afterTextChanged(Editable arg0) {
                // TODO Auto-generated method stub
            }
        });
}


@Override
public void onItemClick(AdapterView<?> arg0, View v, int position, long arg3) {
// TODO Auto-generated method stub
Intent i;
String name = adapter1.getItem(position);
        Log.d("id", name);
if (name.equals("Item1"))
{
    i = new Intent(this, anActivity.class);
    startActivity(i);
}
else if (name.equals("Item2"))
{
    i = new Intent(this, anActivity2.class);
    startActivity(i);
}
}
}


class SingleRow {
String pagedata;
SingleRow(String pagedata){
    this.pagedata=pagedata;
}
}
class PagesAdapter extends BaseAdapter implements Filterable{
ArrayList<String> pagelist;
List<String> arrayList;
Context context;
String [] pagedatas;

PagesAdapter(Context c){
context=c;
pagelist = new ArrayList<String>();
Resources res = c.getResources();
pagedatas = res.getStringArray(R.array.pages_data);

for (int i=0;i<463;i++){
    pagelist.add(pagedatas[i]);
}
arrayList = pagelist;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return arrayList.size();
}

@Override
public void notifyDataSetChanged() {
super.notifyDataSetChanged();
}

@Override
public String getItem(int i) {
// TODO Auto-generated method stub
return arrayList.get(i);
}

@Override
public long getItemId(int i) {
// TODO Auto-generated method stub
return i;
}


@Override
public View getView(int i, View view, ViewGroup viewG) {
// TODO Auto-generated method stub
LayoutInflater inflater=(LayoutInflater)                 context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View row=inflater.inflate(R.layout.single_row,viewG,false);
TextView pagetitle = (TextView) row.findViewById(R.id.textViewRow);

String temp=arrayList.get(i);

pagetitle.setText(temp);
return row;
}

@Override
public Filter getFilter() {
// TODO Auto-generated method stub
Filter filter = new Filter() {
    @SuppressWarnings("unchecked")
    @Override
    protected void publishResults(CharSequence constraint, FilterResults results) {

        arrayList = (List<String>) results.values;
        notifyDataSetChanged();
    }

    @Override
    protected FilterResults performFiltering(CharSequence constraint) {

     FilterResults results = new FilterResults();
        ArrayList<String> FilteredArrayNames = new ArrayList<String>();

        if (pagelist == null)    {
            pagelist = new ArrayList<String>(arrayList);
        }
        if (constraint == null || constraint.length() == 0) {
            results.count = pagelist.size();
            results.values = pagelist;
        } else {
            constraint = constraint.toString().toLowerCase();
            for (int i = 0; i < pagelist.size(); i++) {
                String dataNames = pagelist.get(i);
                if (dataNames.toLowerCase().startsWith(constraint.toString()))  {
                    FilteredArrayNames.add(dataNames);
                }
            }

            results.count = FilteredArrayNames.size();
            System.out.println(results.count);

            results.values = FilteredArrayNames;
            Log.e("VALUES", results.values.toString());
        }

        return results;
}
};
return filter;
}
}

Answer 3

怎么放

adapter1.notifyDataSetChanged();

在Activity的onResume()方法中？