Android实战简易教程-第五枪（ListView用法研究）

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徐的张 2022-11-11 11:06:05 博主文章分类： Android ©著作权

文章标签 Android ListView android xml bundle 文章分类 运维

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Android用的最多的，也最难用的应该就是ListView了，下面我们研究一下它的用法。

一、最简单的ListView

我们简单介绍一下ListView的最简单用法，不用布局文件：

package org.lxh.demo;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends Activity {
  private String[] arrays = { "Sunday", "Monday", "Tuesday", "Wednesday",
      "Thursday", "Friday", "Saturday" };
  private ListView listView;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    listView = new ListView(this);
    listView.setAdapter(new ArrayAdapter<String>(this,
        android.R.layout.simple_expandable_list_item_1, arrays));//利用ArrayAdapter对数据进行包装
    super.setContentView(listView);//将ListView设置为显示界面
  }

}

运行实例如下：

Android实战简易教程-第五枪（ListView用法研究）_xml

二、结合ArrayAdapter实现较复杂的ListView

1.main.xml代码：

<p><?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" ></p><p>    <ListView
        android:id="@+id/list_view"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" /></p><p></LinearLayout></p>

2.fruit_item.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <ImageView
        android:id="@+id/fruit_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/fruit_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginLeft="10sp" />
</LinearLayout>

3.Fruit.java代码如下：

package org.lxh.demo;

public class Fruit {
  private String name;
  private int imageId;

  public Fruit(String name, int imageId) {
    this.name = name;
    this.imageId = imageId;
  }

  public String getName() {
    return name;
  }

  public int getImageId() {
    return imageId;
  }
}

4.集成ArrayAdapter的FruitAdapter.java代码如下：

package org.lxh.demo;

import java.util.List;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class FruitAdapter extends ArrayAdapter<Fruit> {
  private int resourceId;

  public FruitAdapter(Context context, int textViewResourceId,
      List<Fruit> objects) {
    super(context, textViewResourceId, objects);
    resourceId = textViewResourceId;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
    Fruit fruit = getItem(position);
    View view;
    ViewHolder viewHolder;
    if (convertView == null) {
      view = LayoutInflater.from(getContext()).inflate(resourceId, null);
      viewHolder = new ViewHolder();
      viewHolder.fruitImage = (ImageView) view
          .findViewById(R.id.fruit_image);
      viewHolder.fruitName = (TextView) view
          .findViewById(R.id.fruit_name);
      view.setTag(viewHolder);
    } else {
      view = convertView;
      viewHolder = (ViewHolder) view.getTag();
    }

    viewHolder.fruitImage.setImageResource(fruit.getImageId());
    viewHolder.fruitName.setText(fruit.getName());
    return view;

  }

  class ViewHolder {
    ImageView fruitImage;
    TextView fruitName;
  }

}

5.MainActivity.java代码如下：

package org.lxh.demo;

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

import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;

public class Hello extends Activity {
  private List<Fruit> fruitList = new ArrayList<Fruit>();

  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState); // 生命周期方法
    super.setContentView(R.layout.main); // 设置要使用的布局管理器
    initFruits();
    FruitAdapter adapter = new FruitAdapter(Hello.this,
        R.layout.fruit_item, fruitList);
    ListView listView = (ListView) findViewById(R.id.list_view);
    listView.setAdapter(adapter);

  }

  private void initFruits() {
    Fruit appleFruit = new Fruit("Apple", R.drawable.apple_pic);
    fruitList.add(appleFruit);
    Fruit bananaFruit = new Fruit("Banana", R.drawable.banana_pic);
    fruitList.add(bananaFruit);
    Fruit orangeFruit = new Fruit("Orange", R.drawable.orange_pic);
    fruitList.add(orangeFruit);
    Fruit waterFruit = new Fruit("Apple", R.drawable.watermelon_pic);
    fruitList.add(waterFruit);

  }
}

运行实例如下：

三、结合上下文菜单实现单项的删除

修改MainActivity.java程序如下：

package org.lxh.demo;

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

import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.ListView;
import android.widget.AdapterView.AdapterContextMenuInfo;

public class Hello extends Activity {
  private List<Fruit> fruitList = new ArrayList<Fruit>();
  FruitAdapter adapter;

  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState); // 生命周期方法
    super.setContentView(R.layout.main); // 设置要使用的布局管理器
    initFruits();
    adapter = new FruitAdapter(Hello.this, R.layout.fruit_item, fruitList);
    ListView listView = (ListView) findViewById(R.id.list_view);
    listView.setAdapter(adapter);
    super.registerForContextMenu(listView);//注册上下文菜单

  }

  @Override
  public void onCreateContextMenu(ContextMenu menu, View v,// 创建菜单项
      ContextMenuInfo menuInfo) {

    super.onCreateContextMenu(menu, v, menuInfo);
    menu.setHeaderTitle("选择操作");
    menu.add(Menu.NONE, Menu.FIRST + 1, 1, "删除");
    menu.add(Menu.NONE, Menu.FIRST + 2, 2, "取消");
  }

  @Override
  public boolean onContextItemSelected(MenuItem item) {// 选择监听
    AdapterContextMenuInfo acmiRef = (AdapterContextMenuInfo) item
        .getMenuInfo();// 用来获取item信息哎，重要
    int removeIndex = acmiRef.position;
    switch (item.getItemId()) {
    case Menu.FIRST + 1:
      fruitList.remove(removeIndex);
      adapter.notifyDataSetChanged();// 删除后刷新ListView

      break;
    case Menu.FIRST + 2:

      break;

    default:
      break;
    }
    return false;
  }

  private void initFruits() {
    Fruit appleFruit = new Fruit("Apple", R.drawable.apple_pic);
    fruitList.add(appleFruit);
    Fruit bananaFruit = new Fruit("Banana", R.drawable.banana_pic);
    fruitList.add(bananaFruit);
    Fruit orangeFruit = new Fruit("Orange", R.drawable.orange_pic);
    fruitList.add(orangeFruit);
    Fruit waterFruit = new Fruit("Apple", R.drawable.watermelon_pic);
    fruitList.add(waterFruit);

  }
}