从android中的自定义列表适配器调用活动方法？

Question

单击按钮我正在尝试使用 google 的 volley 库将一些数据发送到我的 php 脚本。发送数据的方法在 Activity 内部，我编写了一个接口来从 自定义列表适配器。

以下是我的适配器代码：

public class RoleList extends ArrayAdapter<String> {

    public static final String DELETEUSERINFO = VirtualMachineIp.VMIP_ADDRESS.trim() + "goldmine/getuserinfo.php";
    public static final String KEY_NAME = "name";
    public static final String KEY_ROLE = "role";
    private ArrayList<String> name;
    private ArrayList<String> username;
    private ArrayList<String> password;
    private ArrayList<String> role;
    private Activity context;

    public int getPos() {
        return pos;
    }

    public void setPos(int pos) {
        this.pos = pos;
    }

    int pos;

    public boolean isDelPressed() {
        return delPressed;
    }

    public void setDelPressed(boolean delPressed) {
        this.delPressed = delPressed;
    }

    boolean delPressed;

    private onDelCallback listener;

    public RoleList(Activity context, ArrayList<String> name, ArrayList<String> username, ArrayList<String> password, ArrayList<String> role, onDelCallback listener) {
        super(context, R.layout.role_list, name);
        this.context = context;
        this.name = name;
        this.username = username;
        this.password = password;
        this.role = role;
        this.listener = listener;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = context.getLayoutInflater();
        final View listViewItem = inflater.inflate(R.layout.role_list, null, true);
        final TextView textViewName = (TextView) listViewItem.findViewById(R.id.tv_empname);
        final TextView textViewusername = (TextView) listViewItem.findViewById(R.id.tv_empusername);
        final TextView textViewPass = (TextView) listViewItem.findViewById(R.id.tv_emppassword);
        final TextView textViewRole = (TextView) listViewItem.findViewById(R.id.tv_emprole);
        Button edit = (Button) listViewItem.findViewById(R.id.btn_editRole);
        Button delete = (Button) listViewItem.findViewById(R.id.btn_delRole);


        delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                setDelPressed(true);
                name.remove(position);
                username.remove(position);
                password.remove(position);
                role.remove(position);
                listener.deleteuser(position);
                notifyDataSetChanged();
                setPos(position);

            }
        });
        edit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d("Emp Info", name.get(position) + " " + username.get(position) + " " + password.get(position) + " " + role.get(position));

                final Dialog dialog = new Dialog(getContext());
                dialog.setContentView(R.layout.userreg);
                dialog.setTitle("Edit Employee " + name.get(position) + " details");
                final String[] arraySpinner = new String[]{"Manager", "Stockist", "Cashier", "Accountant"};
                dialog.setCancelable(false);
                dialog.setCanceledOnTouchOutside(false);
                final EditText emp_name = (EditText) dialog.findViewById(R.id.editTextName);
                final EditText emp_uname = (EditText) dialog.findViewById(R.id.editTextUserName);
                final EditText emp_pw = (EditText) dialog.findViewById(R.id.editTextPassword);
                final Spinner emp_role = (Spinner) dialog.findViewById(R.id.spinner_role);
                final TextView textRole = (TextView) dialog.findViewById(R.id.tv_selected_role);
                ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(), android.R.layout.simple_spinner_item, arraySpinner);
                emp_role.setAdapter(adapter);
                emp_role.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                    @Override
                    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                        Toast.makeText(getContext(), "Role Selected is " + arraySpinner[position], Toast.LENGTH_SHORT).show();

                        String employee_role = arraySpinner[position];
                        textRole.setText(employee_role);

                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> parent) {

                    }
                });


                emp_name.setText(name.get(position));
                emp_uname.setText(username.get(position));
                emp_pw.setText(password.get(position));
                emp_role.setSelection(position);

                Button buttoncancel = (Button) dialog.findViewById(R.id.buttonCancel);
                buttoncancel.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        dialog.dismiss();
                    }
                });

                Button buttonChange = (Button) dialog.findViewById(R.id.buttonRegister);
                buttonChange.setText("Change");
                buttonChange.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        textViewName.setText(emp_name.getText().toString());
                        textViewusername.setText(emp_uname.getText().toString());
                        textViewPass.setText(emp_pw.getText().toString());
                        textViewRole.setText(textRole.getText());
                        dialog.dismiss();

                    }
                });


                dialog.show();
            }
        });


        textViewName.setText(name.get(position));
        textViewusername.setText(username.get(position));
        textViewPass.setText(password.get(position));
        textViewRole.setText(role.get(position));

        return listViewItem;
    }

    public interface onDelCallback {
        void deleteuser(int pos);
    }



}

理想情况下，当按下列表中的按钮时，应该调用以下代码：

@Override
    public void deleteuser(final int pos)
    {
        StringRequest stringRequest = new StringRequest(Request.Method.POST, DELETEUSERINFO, new Response.Listener<String>() {
            @Override
            public void onResponse(String response)
            {
                String resp = response.toString().trim();
                if (resp.equals("UNABLE TO DELETE USER"))
                {
                    Log.d("UNABLE TO DEL",resp);
                }else if (resp.equals("USER DELETED SUCCESSFULLY"))
                {
                    Toast.makeText(UserRegistration.this, "USER DELETED SUCCESSFULLY", Toast.LENGTH_SHORT).show();
                }

            }
        },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {

                        Toast.makeText(UserRegistration.this, "Please check your internet connection", Toast.LENGTH_LONG).show();
                    }
                }){

            @Override
            protected Map<String, String> getParams() throws AuthFailureError {
                Map<String, String> params = new HashMap<>();
                params.put(KEY_NAME, employee_name.get(pos));
                params.put(KEY_ROLE,employee_role.get(pos));
                return params;
            }
        };
        RequestQueue rq = Volley.newRequestQueue(this);
        rq.add(stringRequest);
    }

我在 parseUserinfo() 中设置了适配器，它在 getUserinfo() 的响应上运行，我在 onCreate().getUserinfo() 中调用它用于从远程服务器请求数据。

这是我设置适配器的方式：

 RoleList roleList = new RoleList(UserRegistration.this, employee_name, emp_username, emp_password, employee_role,UserRegistration.this);
 userList.setAdapter(roleList);

我想知道我是否在正确的位置调用了适配器。我需要再次调用它吗？

感谢任何帮助或建议。谢谢。

Answer 1

您可以通过某些方式从适配器调用您的活动方法：

1. 当您当时创建适配器的构造函数时，您可以在其参数中传递您的活动对象，然后在您的适配器中使用该对象。

2. 如果您在适配器中创建接口，则必须在各自的活动中实现该接口，然后您可以通过适配器构造函数传递活动对象并可以使用所需的方法。

Answer 2

public RoleList(Activity context, ArrayList name, ArrayList username, ArrayList password, ArrayList role, onDelCallback listener) { } 在上面的构造函数中，你必须传递相应的 Activity 对象，例如 MyActvity mActivity，而不是传递通用的 Activity 对象。我希望您的方法在 MyActvity 类中可用，并且考虑到您已经在 MyActvity 类上实现了接口。

Answer 3

您可以像这样在适配器中执行您的活动的删除任务

delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                UserRegistration act = (UserRegistration) context;
                act.deleteuser(position);
            }
        });