Question

我正在尝试使用Textview和复选框创建自定义列表视图，列表将被创建，以便用户通过将其写入自定义对话框将项目添加到列表中。

我的代码如下：

 package ayush.lists;

import android.app.Activity;
import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class Current extends Activity {
    Model list[] = new Model[100];
    String s;
    int i = 0;
    final Context context = this;
    Dialog dia = new Dialog(context);
    ListView l1 = (ListView) findViewById(R.id.listView1);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_current);
        Button addi = (Button) findViewById(R.id.bt1);
        Button sav = (Button) findViewById(R.id.bt2);
        addi.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                StartDialog();
            }
        });

    }

    public void StartDialog() {
        dia.setTitle("Add Item");
        dia.setContentView(R.layout.cust_dialog);
        TextView t2 = (TextView) dia.findViewById(R.id.textView1);
        t2.setText("Name of the Item:");
        Button add = (Button) dia.findViewById(R.id.button1);
        Button add_another = (Button) dia.findViewById(R.id.button2);
        Button cancel = (Button) dia.findViewById(R.id.button3);
        EditText item = (EditText) dia.findViewById(R.id.editText1);
        s = item.getText().toString();
        list[i++] = new Model(s, 0);
        add.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if (s.length() >= 0) {
                    CustList adapter = new CustList(v.getContext(), list);
                    l1.setAdapter(adapter);
                    dia.dismiss();
                } else
                    Toast.makeText(getApplicationContext(),
                            "Please Enter Valid Input", 2000).show();
            }
        });

        add_another.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                if (s.length() >= 0) {
                    CustList adapter = new CustList(v.getContext(), list);
                    l1.setAdapter(adapter);
                    dia.dismiss();
                    StartDialog();
                } else
                    Toast.makeText(getApplicationContext(),
                            "Please Enter Valid Input", 2000).show();
            }
        });
        cancel.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                dia.dismiss();
            }
        });
        dia.show();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.current, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

自定义适配器的代码是

package ayush.lists;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.TextView;

public class CustList extends ArrayAdapter<Model> {
    Model[] modelItems = null;
    Context context;

    public CustList(Context context, Model[] resource) {
        super(context, R.layout.list_item, resource);
        // TODO Auto-generated constructor stub
        this.context = context;
        this.modelItems = resource;
    }

    @SuppressLint("ViewHolder")
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        LayoutInflater inflater = ((Activity) context).getLayoutInflater();
        convertView = inflater.inflate(R.layout.list_item, parent, false);
        TextView name = (TextView) convertView.findViewById(R.id.textView1);
        CheckBox cb = (CheckBox) convertView.findViewById(R.id.checkBox1);
        name.setText(modelItems[position].getName());
        if (modelItems[position].getValue() == 1)
            cb.setChecked(true);
        else
            cb.setChecked(false);
        return convertView;
    }
}

你能告诉我为什么这不起作用。我最近开始进行android编程，可能会有很多错误，我会很感激所有的反馈。如果可能，请更正代码并回答。

Answer 1

添加

final Context context = this;
Dialog dia = new Dialog(context);
ListView l1 = (ListView) findViewById(R.id.listView1);

<{1>}方法中的

，因为Activity方法中提供了onCreate。改变

activity context

到

final Context context = this;
Dialog dia = new Dialog(context);
ListView l1 = (ListView) findViewById(R.id.listView1);

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

有人可以告诉我为什么这个Android代码不起作用？

1 个答案: