弹出菜单不适用于 arrayAdapter 列表视图答案

【问题标题】：Popup menu not working on arrayAdapter listview弹出菜单不适用于 arrayAdapter 列表视图
【发布时间】：2017-08-11 20:31:37
【问题描述】：

我有一个图像视图作为数组 adpater / listview 的一部分。 imageView 是列表视图中每个项目左侧的设置图标。当用户单击图像时，会出现一个弹出菜单。但到目前为止，我无法显示菜单。我已经为图像创建了一个 setOnClickListener，但仍然不行。有人可以告诉我我在这里做错了什么。弹出菜单的实现是在适配器还是在活动中完成的？到目前为止，我都尝试过，但都不起作用。谢谢主活动

package com.example.george.hostscanmenus;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.PopupMenu;
import android.widget.TextView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {

    List hostList;
    ArrayAdapter<String> hostAdapter;
    PopupMenu popup;
    String subnet = "192.168.10.";
    ListView listView;

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

        hostList = new ArrayList<String>();


        //populating host addresses
        for(int i = 0; i < 255; i++) {
            hostList.add(subnet+i +"-aa:bb:00:cc:33:ee");
        }

        //inflating adapter
        listView = (ListView) findViewById(R.id.scan_list);
        hostAdapter = new ArrayAdapter<String>(getApplicationContext(), R.layout.host_item, R.id.ip_address, hostList);
        listView.setAdapter(hostAdapter);


    }

}

适配器

package com.example.george.hostscanmenus;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.PopupMenu;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;

/**
 * Created by george on 8/11/17.
 */

public class HostAdapter extends ArrayAdapter<String> {

    public HostAdapter(Context context, int num, ArrayList<String> allHost) {
        super(context, 0, allHost);
    }

    @NonNull
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // Get the data item for this position
        String host = getItem(position);
        // Check if an existing view is being reused, otherwise inflate the view
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.activity_main, parent, false);
        }
        // Lookup view for data population
        ImageView settingImgView = (ImageView) convertView.findViewById(R.id.settings_img);
        ImageView nodeHostImgView = (ImageView) convertView.findViewById(R.id.host_icon);
        TextView nodeIpTxtView = (TextView) convertView.findViewById(R.id.ip_address);
        TextView nodeMacTxtView = (TextView) convertView.findViewById(R.id.mac_address);
        ImageView nodeArrowImgView = (ImageView) convertView.findViewById(R.id.port_scan_arrow);
        // Populate the data into the template view using the data object
        settingImgView.setImageResource(R.drawable.ic_action_more_vert);
        nodeHostImgView.setImageResource(R.drawable.ic_computer_white_24dp);
        nodeIpTxtView.setText(host.substring(0,host.indexOf("-")));
        nodeMacTxtView.setText(host.substring(host.indexOf("-")));
        nodeArrowImgView.setImageResource(R.drawable.ic_keyboard_arrow_right_white_24dp);

        settingImgView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showPopupMenu(view);
            }
        });

        // Return the completed view to render on screen
        return convertView;
    }


    /* code for popup menu in listview */
    public void showPopupMenu(View v) {
        PopupMenu popup = new PopupMenu(getContext(), v);
        popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
            @Override
            public boolean onMenuItemClick(MenuItem menuItem) {
                switch (menuItem.getItemId()) {
                    case R.id.change_icon:
                        Toast.makeText(getContext(), menuItem.getTitle(), Toast.LENGTH_SHORT).show();
                        return true;
                    case R.id.notifications:
                        Toast.makeText(getContext(), menuItem.getTitle(), Toast.LENGTH_SHORT).show();
                        return true;
                    default:
                        return false;
                }
            }
        });

        MenuInflater inflater = popup.getMenuInflater();
        inflater.inflate(R.menu.host_menu, popup.getMenu());
        popup.show();
    }

}

列表项xml文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <LinearLayout
        android:id="@+id/text_container"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/settings_img"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="0.10"
            android:padding="3dp"
            android:src="@drawable/ic_action_more_vert"/>

        <ImageView
            android:id="@+id/host_icon"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="0.20"
            android:padding="5dp"
            android:src="@drawable/ic_computer_white_24dp"/>

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.50"
            android:orientation="vertical"
            android:paddingLeft="0dp"
            >

            <TextView
                android:id="@+id/ip_address"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textSize="18dp"
                tools:text="192.168.10.100"
                />

            <TextView
                android:id="@+id/mac_address"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textSize="16dp"
                tools:text="aa:bb:cc:00:11:22"
                />
        </LinearLayout>

        <ImageView
            android:id="@+id/port_scan_arrow"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="0.20"
            android:padding="5dp"
            android:src="@drawable/ic_keyboard_arrow_right_white_24dp"/>

    </LinearLayout>
</RelativeLayout>

主xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:ads="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:id="@+id/scan_list_linear"
    tools:context=".MainActivity">

    <!--Listview to display scan output-->
    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/scan_list"/>

</LinearLayout>

菜单xml

<!-- listview menu for host scan options eg:
     change hostname, icon, notification etc -->
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <!-- Settings, should always be in the overflow -->
    <item android:id="@+id/change_icon"
        android:title="change icon"
        />


    <item android:id="@+id/notifications"
        android:title="set notification"
        />

</menu>

【问题讨论】：

标签： android xml listview android-arrayadapter popupmenu

【解决方案1】：

弹出菜单是从一个活动而不是上下文创建的。因此，首先在适配器的构造函数中添加活动。您将活动的上下文发送到 super() 并将活动保存在私有字段变量中。

公共类 HostAdapter 扩展 ArrayAdapter { 私人活动活动；
public HostAdapter(Activity 活动, int num, ArrayList allHost) {
super(activity.getApplicationContext(), 0, allHost);
this.activity = 活动；
}

现在在您的弹出方法中，使用该活动而不是 getContext()。

public void showPopupMenu(View v) {
PopupMenu popup = new PopupMenu(活动, v);
// 继续你的工作

【讨论】：