Question

我想在ListView中显示包含多个列的数组。

调用View.getView()时出现此错误：

android.widget.linerlayout无法强制转换为android.widget.textview

public class Lista extends Activity {

    ListView lstProductos;
    EditText txtNombre;
    EditText txtEdad;
    String message;
    List<Detalle> Matriz_Detalle;

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

                //lstDetalle = new ListView(this);
        lstProductos = (ListView) findViewById(R.id.lstProductos);
        Matriz_Detalle  = new ArrayList<Detalle>();

        // fill the ArrayList:

        Matriz_Detalle.add(new Detalle("Name1", 25));
        Matriz_Detalle.add(new Detalle("Name2", 30));
        Matriz_Detalle.add(new Detalle("Name3", 40));
        MyAdapter adapter = new MyAdapter(Matriz_Detalle);
        // apply the Adapter:
        lstProductos.setAdapter(adapter);

        lstProductos.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Detalle g = (Detalle) parent.getItemAtPosition(position);
                Toast.makeText(
                        getApplicationContext(),
                        g.getName() + " is " + g.getAge() + " years old.",
                        Toast.LENGTH_LONG
                ).show();
            }
        });
    }
    private class MyAdapter extends BaseAdapter implements ListAdapter {

        private final List<Detalle> data;

        public MyAdapter(List<Detalle> data){
            this.data = data;
        }

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

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

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

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

            TextView Nombre;
            TextView Edad;

            try{


            if (convertView == null) {
                LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                convertView = vi.inflate(R.layout.prueba, null);
                Nombre = (TextView) convertView.findViewById(R.id.txtNombre);
                Edad = (TextView) convertView.findViewById(R.id.txtEdad);
            }else{
                Edad = (TextView) convertView;
                Nombre = (TextView) convertView;
            }

            Edad.setText(data.get(position).name);
            Nombre.setText(data.get(position).name);


            } catch (Exception e) {
                message = e.getMessage();
                Toast.makeText(getBaseContext(), message, Toast.LENGTH_LONG).show();
            }
            return convertView;
        }

    }

    private class Detalle{
        private final String name;
        private final int age;

        public Detalle(String name, int age){
            this.name = name;
            this.age = age;
        }

        public String getName() {
            return name;
        }

        public int getAge() {
            return age;
        }
    }

Answer 1

您尝试将convertView投射到TextView。

将您的getView()更改为：

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
       LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);

       if (convertView == null)
            convertView = vi.inflate(R.layout.prueba, null); 

       TextView = Nombre = (TextView) convertView.findViewById(R.id.txtNombre);
       TextView Edad = (TextView) convertView.findViewById(R.id.txtEdad);

       Edad.setText(data.get(position).name);
       Nombre.setText(data.get(position).name);

       return convertView;
    }

Answer 2

convertView是ListView的项目，因此当您尝试将其投放到TextView或EditText时，会发生ClassCastException！要重用convertView，您应该创建一个内部类ViewHolder:

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

        try{


        if (convertView == null) {
            mHolder = new ViewHolder();
            LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = vi.inflate(R.layout.prueba, null);
            mHolder.nombre = (TextView) convertView.findViewById(R.id.txtNombre);
            mHolder.edad = (TextView) convertView.findViewById(R.id.txtEdad);

            convertView.setTag(mHolder);
        }else{
            mHolder = (ViewHolder) convertView.getTag();
        }

            mHolder.edad.setText(data.get(position).name);
            mHolder.nombre.setText(data.get(position).name);

        } catch (Exception e) {
            message = e.getMessage();
            Toast.makeText(getBaseContext(), message, Toast.LENGTH_LONG).show();
        }
        return convertView;
    }

class ViewHolder {
    TextView nombre;
    TextView edad;
}

显示多列listview baseAdapter

2 个答案: