Question

我正在创建一个cutomized listView。 listView中每个项目的模型如“model_view”布局所示。我将数据设置为适配器，如下面的“set adapter”所示。 cutomized适配器如“CutomizedAdapter”

所示

当我运行应用程序时，屏幕上没有出现任何项目

为什么列表视图的项目没有显示

model_view ：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
    android:id="@+id/tvName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight=".3"
    android:text="Name"/>

<TextView
    android:id="@+id/tvAddress"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight=".3"
    android:text="Address: "/>

<TextView
    android:id="@+id/tvGender"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight=".3"
    android:text="gender: "/>
</LinearLayout>

设置适配器：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    this.mListView = (ListView) findViewById(R.id.listview);
    this.mModelList = new ArrayList<RowModel>();

    this.mModelList.add(new RowModel("xx", "Mümchen", "M"));
    this.mModelList.add(new RowModel("xx", "Karlsruhe", "M"));
    this.mModelList.add(new RowModel("xx", "Mümchen", "F"));
    this.mModelList.add(new RowModel("xx", "Karlsruhe", "F"));
    this.mModelList.add(new RowModel("xx", "Alexandria", "M"));
    this.mModelList.add(new RowModel("xx", "Cairo", "F"));

    CustomizedAdapter adapter = new CustomizedAdapter(this, R.layout.model_view, this.mModelList);
    this.mListView.setAdapter(adapter);

CutomizedAdapter ：

public class CustomizedAdapter extends BaseAdapter {

private Context mCxt = null;
private int mRowModelLayout;
private ArrayList<RowModel> mRowsList = null;
private static LayoutInflater inflater=null;

public CustomizedAdapter(Context cxt, int rowModelLayout, ArrayList<RowModel> rowsList) {
    this.mCxt = cxt;
    this.mRowModelLayout = rowModelLayout;
    this.mRowsList = rowsList;
}

@Override
public int getCount() {
    return 0;
}

@Override
public Object getItem(int position) {
    return null;
}

@Override
public long getItemId(int position) {
    return 0;
}

public static class ViewHolder{
    public TextView tvName;
    public TextView tvAddress;
    public TextView tvGender;
}

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

    final int pos = position;
    ViewHolder holder = new ViewHolder();
    View rowView;

    convertView = inflater.inflate(R.layout.model_view, null);
    holder.tvName=(TextView) convertView.findViewById(R.id.tvName);
    holder.tvAddress=(TextView) convertView.findViewById(R.id.tvAddress);
    holder.tvGender=(TextView) convertView.findViewById(R.id.tvGender);

    convertView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Toast.makeText(mCxt, "You Clicked "+mRowsList.get(pos).getName(), Toast.LENGTH_LONG).show();
        }
    });
    return convertView;
}
}

Answer 1

为什么你不填写以下方法？

@Override
public int getCount() {
    return mRowsList.size();
}

@Override
public Object getItem(int position) {
    return mRowsList.get(position);
}

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

此外，您尚未初始化inflater

所以，在你的构造函数中初始化它，如

public CustomizedAdapter(Context cxt, int rowModelLayout, ArrayList<RowModel> rowsList) {
    this.mCxt = cxt;
    this.mRowModelLayout = rowModelLayout;
    this.mRowsList = rowsList;
    inflater = (LayoutInflater) cxt.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

Answer 2

因为你在这些方法中返回了错误的东西：

@Override
public int getCount() {
    return 0;
}

@Override
public Object getItem(int position) {
    return null;
}

@Override
public long getItemId(int position) {
    return 0;
}

这些函数不会返回任何内容，请将其更改为：

@Override
public int getCount() {
    return mRowList.size();
}

@Override
public Object getItem(int position) {
    return mRowList.get(position);
}

@Override
public long getItemId(int position) {
    return position; //or mRowList.get(position).getID()
}

列表视图的项目未显示

2 个答案: