列表视图适配器不工作,未调用getView.

Question

我想我变得疯了.如此简单的东西将自定义适配器绑定到Listview让我头疼.

发布代码然后解释:

MainActivity.java

package com.example.pruebalist;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends Activity {

    private static String[] data = new String[] {"0","1","2","3"};

    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        Log.v("MainActivity","Inside MainActivity");
        setContentView(R.layout.main);
        ListView lstView = (ListView)findViewById(R.id.listNoticias);

        ArrayAdapter<String> adapter = new LstAdapter(this, R.layout.row, data);
        lstView.setAdapter(adapter);
    }

}

LstAdapter.java

package com.example.pruebalist;

import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class LstAdapter extends ArrayAdapter<String>{

    private String[] mData;
    private Context mContext;
    int layoutResourceId;

    public LstAdapter(Context context, int textViewResourceId, String[] values) {
        super(context, textViewResourceId, values);
        mContext = context;
        mData = values;
        layoutResourceId = textViewResourceId;

        Log.v("LstAdapter","Inside LstAdapter");
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        View v = convertView;
        Log.v("LstAdapter","Inside getView");

        if(v==null){
            LayoutInflater inflater = ((Activity)mContext).getLayoutInflater();
            v = inflater.inflate(layoutResourceId, parent,false);
        }

        String item = mData[position];
        if(item!=null){
            TextView txtItem = (TextView)v.findViewById(R.id.texto);
            if(txtItem!=null){
                txtItem.setText(item);
            }
        }

        return v;
    }

}

ListView永远不会显示.并且从不使用getView,logCat不显示"Inside Getview".

怎么了？

Answer 1

主要问题是

@Override
    public int getCount() {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return 0;
    }

改为

@Override
    public int getCount() {
        // TODO Auto-generated method stub
        return mData.length;
    }

    @Override
    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return mData[arg0];
    }

查看列表视图和列表活动的 Vogella 教程,尝试ViewHolder在列表适配器中使用它将提高您的视图性能.

Answer 2

这是因为您保留了getCount()返回0 的方法的默认实现,因此适配器认为没有要显示的元素ListView.

它应该回来 mData.length

@Override
public int getCount() {
   return mData.length;
}