OnScrollListener不是定制的ListView适配器内部工作 [英] OnScrollListener not working inside custom ListView Adapter
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问题描述
我要赶上我滚动的ListView定制适配器内部事件，因此我在它实施OnScrollListener，但其方法不会被调用。我到处找一个答案，但没有任何运气，没有错误概莫能外。
有什么地方出错了？
ListView控件适配器：
进口的java.util.ArrayList;
进口android.app.Activity;
进口android.content.Context;
进口android.text.Editable;
进口android.text.TextWatcher;
进口android.view.LayoutInflater;
进口android.view.View;
进口android.view.View.OnFocusChangeListener;
进口android.view.ViewGroup;
进口android.view.View.OnClickListener;
进口android.widget.AbsListView;
进口android.widget.AbsListView.OnScrollListener;
进口android.widget.AdapterView;
进口android.widget.AdapterView.OnItemSelectedListener;
进口android.widget.ArrayAdapter;
进口android.widget.Button;
进口android.widget.EditText;
进口android.widget.ImageView;
进口android.widget.Spinner;
公共类PhotosListViewAdapter扩展ArrayAdapter＆LT; ImageItemsSetter＆GT;实现OnScrollListener { DeleteImageListener dListener;
私人上下文的背景下;
私人诠释layoutResourceId;
私人的ArrayList＆LT; ImageItemsSetter＆GT;数据=新的ArrayList＆LT; ImageItemsSetter＆GT;（）; //标准构造
公共PhotosListViewAdapter（上下文的背景下，诠释layoutResourceId，ArrayList的＆LT; ImageItemsSetter＆GT;数据）{
超级（上下文，layoutResourceId，数据）;
this.layoutResourceId = layoutResourceId;
this.context =背景;
this.data =数据;
} 静态类ViewHolder { 公共ImageView的图;
公众的EditText数量;
公共微调微调;
公共按钮删除; } @覆盖
公共查看getView（最终诠释的立场，观点convertView，父母的ViewGroup）{
查看排= convertView;
ViewHolder支架=无效; ImageItemsSetter图像= data.get（位置）; 如果（行== NULL）{
LayoutInflater充气=（（活动）上下文）.getLayoutInflater（）;
行= inflater.inflate（layoutResourceId，父母，假）;
持有人=新ViewHolder（）; holder.Img =（ImageView的）row.findViewById（R.id.Img）; holder.quantity =（EditText上）row.findViewById（R.id.quantity）;
// holder.quantity.addTextChangedListener（新GenericTextWatcher（holder.quantity））; holder.spinner =（微调）row.findViewById（R.id.photo_format）;
holder.delete =（按钮）row.findViewById（R.id.deleteImage）; row.setTag（保持器）;
}其他{
支架=（ViewHolder）row.getTag（）;
} holder.Img.setImageBitmap（image.getTheImage（））;
holder.quantity.setText（image.getQuantity（））;
ArrayAdapter＆LT;＆CharSequence的GT;适配器= ArrayAdapter.createFromResource（背景下，
R.array.formats_array，android.R.layout.simple_spinner_item）;
adapter.setDropDownViewResource（android.R.layout.simple_spinner_dropdown_item）;
holder.spinner.setAdapter（适配器）; //删除按钮
holder.delete.setOnClickListener（新OnClickListener（）{
@覆盖
公共无效的onClick（视图v）{ 如果（dListener！= NULL）{
dListener.onDelete pressed（位置）;
}
}
}）; / *
holder.spinner.setOnItemSelectedListener（新OnItemSelectedListener（）{ @覆盖
公共无效onItemSelected（适配器视图＆LT;＆GT;母公司，观景，
INT POS，长ID）{
dListener.onFormatChanged（parent.getItemAtPosition（POS）的ToString（），data.get（位置）.getName（））;
} @覆盖
公共无效onNothingSelected（适配器视图＆LT;＆GT;母公司）{
// TODO自动生成方法存根
} }）; holder.quantity.addTextChangedListener（新TextWatcher（）{ @覆盖
公共无效afterTextChanged（编辑S）{} @覆盖
公共无效beforeTextChanged（CharSequence中，诠释开始，
诠释计数后INT）{} @覆盖
公共无效onTextChanged（CharSequence中，诠释开始，
INT之前，诠释计数）{
dListener.onQuantityChanged（s.toString（），data.get（位置）.getName（））;
}
}）; * / 返回行;
}
//接口发送所选图像的位置删除
公共无效setDeleteImageListener（DeleteImageListener监听）{
this.dListener =侦听器;
} 公共静态界面DeleteImageListener {
公共无效onDelete pressed（INT位置）;
公共无效onQuantityChanged（字符串数量，字符串名称）;
公共无效onFormatChanged（字符串格式，字符串名称）;
} @覆盖
公共无效onScrollStateChanged（AbsListView观点，诠释scrollState）{
// TODO自动生成方法存根
的System.out.println（状态改为）;
}
@覆盖
公共无效onScroll（AbsListView观点，诠释firstVisibleItem，
INT visibleItemCount，诠释totalItemCount）{
// TODO自动生成方法存根
的System.out.println（scroleld）;
} }
解决方案
您不是叫 setOnScrollListener（本）的任何地方。做它在构造函数中，它应该很好地工作： - ）
在某处，code，你可能有这样的事情：
PhotosListViewAdapter适配器=新PhotosListViewAdapter（）;
someListView.setAdapter（适配器）;
添加
someListView.setOnScrollListener（适配器）;
I need to catch scrolling events inside my custom ListView Adapter, so I have implemented OnScrollListener in it, but its methods are not being called. I was looking everywhere for an answer but without any luck, no errors no exceptions.
What could be wrong?
ListView Adapter:
import java.util.ArrayList;
import android.app.Activity;
import android.content.Context;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnFocusChangeListener;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Spinner;
public class PhotosListViewAdapter extends ArrayAdapter<ImageItemsSetter> implements OnScrollListener {
DeleteImageListener dListener;
private Context context;
private int layoutResourceId;
private ArrayList<ImageItemsSetter> data = new ArrayList<ImageItemsSetter>();
//standard constructor
public PhotosListViewAdapter(Context context, int layoutResourceId, ArrayList<ImageItemsSetter> data) {
super(context, layoutResourceId, data);
this.layoutResourceId = layoutResourceId;
this.context = context;
this.data = data;
}
static class ViewHolder {
public ImageView Img;
public EditText quantity;
public Spinner spinner;
public Button delete;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
View row = convertView;
ViewHolder holder = null;
ImageItemsSetter image = data.get(position);
if (row == null) {
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
row = inflater.inflate(layoutResourceId, parent, false);
holder = new ViewHolder();
holder.Img = (ImageView) row.findViewById(R.id.Img);
holder.quantity = (EditText) row.findViewById(R.id.quantity);
// holder.quantity.addTextChangedListener(new GenericTextWatcher(holder.quantity));
holder.spinner = (Spinner) row.findViewById(R.id.photo_format);
holder.delete = (Button) row.findViewById(R.id.deleteImage);
row.setTag(holder);
} else {
holder = (ViewHolder) row.getTag();
}
holder.Img.setImageBitmap(image.getTheImage());
holder.quantity.setText(image.getQuantity());
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(context,
R.array.formats_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
holder.spinner.setAdapter(adapter);
//The delete button
holder.delete.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (dListener != null) {
dListener.onDeletePressed(position);
}
}
});
/*
holder.spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view,
int pos, long id) {
dListener.onFormatChanged(parent.getItemAtPosition(pos).toString(), data.get(position).getName());
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
// TODO Auto-generated method stub
}
});
holder.quantity.addTextChangedListener(new TextWatcher() {
@Override
public void afterTextChanged(Editable s) { }
@Override
public void beforeTextChanged(CharSequence s, int start,
int count, int after) { }
@Override
public void onTextChanged(CharSequence s, int start,
int before, int count) {
dListener.onQuantityChanged(s.toString(), data.get(position).getName());
}
});
*/
return row;
}
//Interface to send selected image's position for deletion
public void setDeleteImageListener(DeleteImageListener listener) {
this.dListener = listener;
}
public static interface DeleteImageListener {
public void onDeletePressed(int position);
public void onQuantityChanged(String quantity, String name);
public void onFormatChanged(String format, String name);
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
// TODO Auto-generated method stub
System.out.println("state changed");
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// TODO Auto-generated method stub
System.out.println("scroleld");
}
}
解决方案
You are not calling setOnScrollListener(this) anywhere. Do it in the constructor and it should work fine :-)
Somewhere in your code you probably have something like this:
PhotosListViewAdapter adapter = new PhotosListViewAdapter();
someListView.setAdapter(adapter);
Add
someListView.setOnScrollListener(adapter);
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