listview项不显示

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“设置适配器”所示。 的cutomized适配器如图“CutomizedAdapter”

当我运行的应用程序，也有出现在屏幕

为什么列表视图的项目没有显示

model_view没有任何项目：

<?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> 

集适配器：

@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

为什么你没有填写以下方法呢？

@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; 
} 

而且，你不初始化您inflater

所以，初始化它在你的构造类似

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

因为您返回错误的东西在这些方法：

@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() 
}