java - 如何使 BaseAdapter 显示 AlertDialog android 应用程序

Question

我怎样才能使 listView 中 BaseAdapter 中的按钮显示 alertDialog，我试过了但是它意外停止工作(运行时错误)我的代码如下所示。

任何建议

提前致谢

墨拿拉

====更新后=====================

import java.util.List;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MyCasesListAdapter extends BaseAdapter {
    private Context context;

    private List<MyCaseClass> listOfCases;

    // TODO delete it not imp.
    public MyCasesListAdapter() {

        super();

    }

    public MyCasesListAdapter(Context context, List<MyCaseClass> listPhonebook) {
        this.context = context;
        this.listOfCases = listPhonebook;
    }

    public int getCount() {
        return listOfCases.size();
    }

    public Object getItem(int position) {
        return listOfCases.get(position);
    }

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

    public View getView(int position, View convertView, ViewGroup viewGroup) {
        MyCaseClass entry = listOfCases.get(position);

        if (convertView == null) {

            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.mypage_row, null);


        }

        // this is row items..
        // Set the onClick Listener on this button
        Button ConfExpandRegion  = (Button) convertView.findViewById(R.id.expand);
        Button Cancelb = (Button) convertView.findViewById(R.id.cancelCase);
        TextView tvCase = (TextView) convertView.findViewById(R.id.mypage_name);

        //To be a clickable button
        ConfExpandRegion.setFocusableInTouchMode(false);
        ConfExpandRegion.setFocusable(false);
       //For Dialog
        AlertDialog alertDialog = new AlertDialog.Builder(MyCasesListAdapter.this);
       alertDialog.setTitle("Conformation");
       alertDialog.setMessage("Are you sure you want to do ???");
        ConfExpandRegion.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub
                    alertDialog.setButton("Yes", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int which) {
                      // Some code

                       //ConfExpandRegion.setEnabled(false);
                   }

                });

                alertDialog.setButton2("No", new DialogInterface.OnClickListener() {
                   public void onClick(DialogInterface dialog, int which) {
                    // here you can add functions
                    // Do nothing 




                   }
                });

                alertDialog.setIcon(android.R.drawable.ic_dialog_alert);
                alertDialog.show();




        }});

       //To be a clickable button
        Cancelb.setFocusableInTouchMode(false);
        Cancelb.setFocusable(false);
        Cancelb.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub
                MyCaseClass entry = (MyCaseClass) v.getTag();
                listOfCases.remove(entry);
                // listPhonebook.remove(view.getId());
                notifyDataSetChanged();
            }
        });

        // Set the entry, so that you can capture which item was clicked and
        // then remove it
        // As an alternative, you can use the id/position of the item to capture
        // the item
        // that was clicked.
        ConfExpandRegion.setTag(entry);
        Cancelb.setTag(entry);


        // btnRemove.setId(position);


        return convertView;
    }

    public void onClick(View view) {
        MyCaseClass entry = (MyCaseClass) view.getTag();
        listOfCases.remove(entry);
        // listPhonebook.remove(view.getId());
        notifyDataSetChanged();

    }

    private void showDialog(MyCaseClass entry) {
        // Create and show your dialog
        // Depending on the Dialogs button clicks delete it or do nothing
    }

    public void add(MyCaseClass myCaseClass) {
        // TODO Auto-generated method stub
        listOfCases.add(myCaseClass);
    }






}

//=========================================== ===============================

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

public class MyPage extends Activity {

    Button createForm;
    Button ConfExpandRegion, Cancelb;
    String ExpandMsg, CancelMsg;
    boolean b;
    MyCaseClass mycase;
    TextView tvCase;
    AlertDialog alertDialog;

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


        // Moving to anther activity
        createForm = (Button) findViewById(R.id.creat_new_formbtn);
        createForm.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {

                Intent j = new Intent(MyPage.this, CreateNewForm.class);
                startActivity(j);

            }
        });

        // ============================================================================================
        // for list


            ListView list = (ListView) findViewById(R.id.mypage_list);
            list.setClickable(true);

            final List<MyCaseClass> listOfPhonebook = new ArrayList<MyCaseClass>();

            MyCasesListAdapter adapter = new MyCasesListAdapter(this, listOfPhonebook);

            for (MyCaseClass m : All_Static.getMyCaseList())
                adapter.add(new MyCaseClass(m));

            // after fill the adapter.. assign the list to the adapter
            list.setAdapter(adapter);

            list.setOnItemClickListener(new OnItemClickListener() {

                public void onItemClick(AdapterView<?> arg0, View view, int position, long index) {
                    System.out.println("sadsfsf");
                ;
                }
            });
            list.setAdapter(adapter);
        // ========================================================================================

    }



    public void sendSMS(String number, String msg) throws Exception {
        if (!b) {
            SmsManager smsManager = SmsManager.getDefault();
            smsManager.sendTextMessage(number, null, msg, null, null);
        }
        b = true;
    }

    // ========================================================================

}

Answer 1

当您在创建适配器时将“this”作为参数传递时，您是否 100% 确定您正在传递 Activity？

检查的一个好方法是像这样修改应用程序:

向您的适配器添加一个 Activity 参数

private Context context;
private Activity parentActivity;
...
public MyCasesListAdapter(Context context, List<MyCaseClass> listPhonebook, Activity parentActivity) {         
    this.context = context;         
    this.listOfCases = listPhonebook; 
    this.parentActivity = parentActivity;    
} 

像这样创建您的警报对话框...

AlertDialog alertDialog = new AlertDialog.Builder(parentActivity);

最后，像这样调用适配器的构造函数...

MyCasesListAdapter adapter = new MyCasesListAdapter(this, listOfPhonebook, MyPage.this);   

说明:您可能不需要将 Activity 和 Context 传递给您的基本适配器，但我这样做只是为了让您暂时保持其他一切不变。当您实例化适配器时，我不确定“这个”是否真的是一个 Activity 。我在构造函数中将第三个参数定义为“Activity”，以强制您传入一个 Activity。如果您尝试传入不是 Activity 的内容，您将遇到编译错误，因此它应该可以帮助您解决问题。

此外，我刚刚注意到，但问题可能是您更新后的代码仍在尝试使用 MyCasesListAdapter.this 作为上下文创建 AlertDialog，这不是 Activity 。