ArrayAdapter
數(shù)組適配器遭居，僅能顯示一行文本數(shù)據(jù)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView
android:id="@+id/lv_list"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</ListView>
</LinearLayout>
import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class MainActivity extends Activity {
// 定義要顯示的數(shù)據(jù)
private String[] datas = {"張三", "李四", "王五", "麻子", "小強"};
private ArrayAdapter<String> adapter;
private ListView listView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.lv_list);
// 初始化適配器
adapter = new ArrayAdapter<>(this, android.R.layout.simple_expandable_list_item_1, datas);
listView.setAdapter(adapter);
}
}
可以在value創(chuàng)建數(shù)組資源xml文件arrays.xml，在listview中使用entries
<resources>
<string-array name = "list">
<item>張三</item>
<item>李四</item>
<item>王五</item>
<item>麻子</item>
<item>小強</item>
</string-array>
</resources>
<ListView
android:id="@+id/lv_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:entries="@array/list">
</ListView>
datas = getResources().getStringArray(R.array.list);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String result = parent.getItemAtPosition(position).toString();
Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT).show();
}
});
ArrayAdapter參數(shù)說明
- 第一個參數(shù)暮的，context上下文對象
- 第二個參數(shù)护侮，item樣式畜隶，可以使用系統(tǒng)提供享钞，可以自定義TextView
- 第三個參數(shù)，數(shù)據(jù)源
系統(tǒng)提供item樣式
- simple_list_item1卒落，單行文本框（text）
- simple_list_item2羡铲，兩行文本框（title與text）
- simple_list_item_checked，復(fù)選框（已選中）
- simple_list_item_multiple_choice儡毕，復(fù)選框
- simple_list_item_single_choice也切，單選框
SimpleAdapter
簡單適配器
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ListView
android:id="@+id/lv_list"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</ListView>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:id="@+id/iv_image"
android:layout_width="100dp"
android:layout_height="100dp"
android:src="@mipmap/ic_launcher"
android:layout_margin="5dp"/>
<LinearLayout
android:id="@+id/ll_info"
android:layout_width="match_parent"
android:layout_height="100dp"
android:orientation="vertical"
android:layout_marginTop="5dp"
android:layout_marginLeft="10dp">
<TextView
android:id="@+id/tv_theme"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30sp"
android:layout_marginTop="10dp"/>
<TextView
android:id="@+id/tv_content"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="24dp"
android:layout_marginTop="10dp"/>
</LinearLayout>
</LinearLayout>
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class MainActivity extends Activity {
private List<Map<String,Object>> lists;
private SimpleAdapter adapter;
private ListView listView;
// 定義數(shù)據(jù)
private String[] theme = {"張三", "李四", "王五"};
private String[] content = {"我是張三，你好", "我是李四腰湾，你好", "我是王五雷恃，你好"};
private int[] imageViews = {R.mipmap.ic_launcher, R.mipmap.ic_account, R.mipmap.ic_password};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.lv_list);
// 準(zhǔn)備數(shù)據(jù)源
lists = new ArrayList<>();
for(int i = 0; i < theme.length; i++) {
Map<String,Object> map = new HashMap<>();
map.put("image", imageViews[i]);
map.put("theme", theme[i]);
map.put("content", content[i]);
lists.add(map);
}
adapter = new SimpleAdapter(MainActivity.this, lists, R.layout.list_item, new String[]{"image", "theme", "content"}, new int[]{R.id.iv_image, R.id.tv_theme, R.id.tv_content});
listView.setAdapter(adapter);
}
}
SimpleAdapter參數(shù)說明
- 第一個參數(shù)，上下文對象
- 第二個參數(shù)费坊，數(shù)據(jù)源（集合倒槐，元素類型Map）
- 第三個參數(shù)，item布局文件
- 第四個參數(shù)附井，String數(shù)組讨越，數(shù)組元素與數(shù)據(jù)源Map的key一一對應(yīng)
- 第五個參數(shù)，int數(shù)組永毅，item布局文件的控件id
BaseAdapter
import android.content.Context;
import android.text.Layout;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class InfoAdapter extends BaseAdapter {
private List<Message> datas;
private Context mContext;
public MyAdapter(List<Message> datas, Context mContext) {
Datas = datas;
this.mContext = mContext;
}
/**
* 返回item個數(shù)
* @return
*/
@Override
public int getCount() {
return datas.size();
}
/**
* 返回單個item對象
* @param i
* @return
*/
@Override
public Object getItem(int i) {
return datas.get(i);
}
/**
* 返回單個item的id
* @param i
* @return
*/
@Override
public long getItemId(int i) {
return i;
}
/**
* 暫不進行優(yōu)化處理
* @param i
* @param view
* @param viewGroup
* @return
*/
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
view = LayoutInflater.from(mContext).inflate(R.layout.list_item, viewGroup, false);
ImageView iv_image = (ImageView) view.findViewById(R.id.iv_image);
TextView tv_theme = (TextView) view.findViewById(R.id.tv_theme);
TextView tv_content = (TextView) view.findViewById(R.id.tv_content);
iv_image.setImageResource(Datas.get(i).getImageId());
tv_theme.setText(Datas.get(i).getTheme());
tv_content.setText(Datas.get(i).getContent());
return view;
}
}
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends Activity {
private List<Message> lists;
private InfoAdapter adapter;
private ListView listView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.ll_list);
lists = new ArrayList<>();
lists.add(new Message(R.mipmap.ic_launcher, "張三", "你好把跨，我是張三"));
lists.add(new Message(R.mipmap.ic_account, "李四", "你好，我是李四"));
lists.add(new Message(R.mipmap.ic_password, "王五", "你好沼死，我是王五"));
adapter = new InfoAdapter(lists, MainActivity.this);
listView.setAdapter(adapter);
}
}
利用Listview緩存機制但findviewbyid反復(fù)使用
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// 若view未被實例化着逐，緩存池?zé)o對應(yīng)緩存
if (convertView == null) {
convertView = mInflater.inflate(R.layout.item, null);
}
/**
* 獲取item布局文件對應(yīng)控件
*/
ImageView imageView = (ImageView) convertView.findViewById(R.id.iv_image);
TextView titleTextView = (TextView) convertView.findViewById(R.id.tv_theme);
TextView contentTextView = (TextView) convertView.findViewById(R.id.tv_content);
// 獲取相應(yīng)索引ItemBean對象
ItemBean bean = mList.get(position);
/**
* 設(shè)置控件的對應(yīng)屬性值
*/
imageView.setImageResource(bean.itemImageResId);
titleTextView.setText(bean.itemTheme);
contentTextView.setText(bean.itemContent);
return convertView;
}
- 創(chuàng)建bean對象，用于封裝數(shù)據(jù)
- 在構(gòu)造方法中初始化數(shù)據(jù)List
- 創(chuàng)建ViewHolder類意蛀，創(chuàng)建布局映射關(guān)系
- 判斷convertView耸别，為空則創(chuàng)建并設(shè)置tag，不為空則通過tag取出ViewHolder
- 給ViewHolder控件設(shè)置數(shù)據(jù)
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
// 若view未被實例化過县钥，緩存池?zé)o對應(yīng)緩存
if (convertView == null) {
viewHolder = new ViewHolder();
// 僅需將XML轉(zhuǎn)化為View秀姐，不涉及布局，第二個參數(shù)設(shè)置為null
convertView = mInflater.inflate(R.layout.item, null);
// 對viewHolder屬性進行賦值
viewHolder.imageView = (ImageView) convertView.findViewById(R.id.iv_image);
viewHolder.theme = (TextView) convertView.findViewById(R.id.tv_theme);
viewHolder.content = (TextView) convertView.findViewById(R.id.tv_content);
// 通過setTag將convertView與viewHolder關(guān)聯(lián)
convertView.setTag(viewHolder);
} else {
// 若緩存池有對應(yīng)view緩存若贮，則通過getTag取出viewHolder
viewHolder = (ViewHolder) convertView.getTag();
}
// 取出bean對象
ItemBean bean = mList.get(position);
// 設(shè)置控件的數(shù)據(jù)
viewHolder.imageView.setImageResource(bean.itemImageResId);
viewHolder.title.setText(bean.itemTheme);
viewHolder.content.setText(bean.itemContent);
return convertView;
}
// ViewHolder用于緩存控件囊扳，屬性對應(yīng)item布局文件控件
class ViewHolder{
public ImageView imageView;
public TextView theme;
public TextView content;
}
