Android常用UI組件 - ListView

標籤：android   listview   

列表視圖（ListView）是Android當中一個非常重要的組件，它以列表的形式展示具體內容，並且能夠根據資料的長度自適應顯示。

 

列表的顯示需要三個元素：

1．ListVeiw 用來展示列表的View。

2．適配器 用來把資料對應到ListView上的中介。

3．資料 具體的將被映射的字串，圖片，或者基本組件。

 

首先介紹“適配器”這個基礎概念。在列表中定義的資料都通過“適配器”來映射到ListView上，ListView中常用的適配器有兩種：

ArrayAdapter:最簡單的適配器，只能顯示一行文字；

SimpleAdapter:具有很好擴充性的適配器，可以顯示自訂內容。

 

用ArrayAdapter結合ListView進行顯示

運行效果

 

原始碼ActivityList1.java

package com.rainsong.listviewdemo;import java.util.List;import java.util.ArrayList;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener;  import android.widget.ArrayAdapter;import android.widget.ListView;import android.widget.Toast;public class ActivityList1 extends Activity{    ListView listView;    List<String> data;    ArrayAdapter arrayAdapter;    OnItemClickListener listener;    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState)    {        super.onCreate(savedInstanceState);        listView = new ListView(this);        data = new ArrayList<String>();        data.add("Item1");        data.add("Item2");        data.add("Item3");        arrayAdapter = new ArrayAdapter(this,                android.R.layout.simple_list_item_1, data);        listView.setAdapter(arrayAdapter);        listener = new OnItemClickListener() {            public void onItemClick(AdapterView<?> parent,                    View view, int position, long id) {                Toast.makeText(ActivityList1.this, parent.getItemAtPosition(position).toString() + " clicked",Toast.LENGTH_SHORT).show();            }        };        listView.setOnItemClickListener(listener);        setContentView(listView);    }}

API知識點

 

ArrayAdapter

public class

ArrayAdapter

extends BaseAdapter

implements Filterable

ArrayAdapter(Context context, int resource, List<T> objects)

Constructor

ListView

public class

ListView

extends AbsListView

 

ListView(Context context)

void

setAdapter(ListAdapter adapter)

Sets thedata behind this ListView.

 

void

setOnItemClickListener(AdapterView.OnItemClickListener listener)

Register acallback to be invoked when an item in this AdapterView has been clicked.

AdapterView.OnItemClickListener

 public static interface

AdapterView.OnItemClickListener

abstract void

onItemClick(AdapterView<?>parent, View view, int position, long id)

Callbackmethod to be invoked when an item in this AdapterView has been clicked.

AdapterView

public abstract class

AdapterView

extends ViewGroup

 

Object

getItemAtPosition(int position)

Gets the data associated with the specified position in the list.

 

 

Toast

public class

Toast

extends Object

 

Constants

int        LENGTH_LONG        Showthe view or text notification for a long period of time.

int        LENGTH_SHORT        Showthe view or text notification for a short period of time.

 

static Toast

makeText(Context context, int resId, int duration)

Make a standard toast that just contains a text view with the text from a resource.

 

static Toast

makeText(Context context, CharSequence text, int duration)

Make a standard toast that just contains a text view.

 

void

show()

Show the view for the specified duration.

 

用SimpleAdapter結合ListView進行顯示

運行效果

 

 

原始碼ActivityList2.java

 

package com.rainsong.listviewdemo;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener;  import android.widget.ListView;import android.widget.SimpleAdapter;import android.widget.Toast;public class ActivityList2 extends Activity{    private List<Map<String, Object>> data;    private ListView listView;    private SimpleAdapter adapter;    OnItemClickListener listener;    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState)    {        super.onCreate(savedInstanceState);        data = new ArrayList<Map<String, Object>>();        Map<String, Object> item;        item = new HashMap<String, Object>();        item.put("姓名", "張三");        item.put("性別", "男");        data.add(item);        item = new HashMap<String, Object>();        item.put("姓名", "李四");        item.put("性別", "男");        data.add(item);        item = new HashMap<String, Object>();        item.put("姓名", "王五");        item.put("性別", "男");        data.add(item);        item = new HashMap<String, Object>();        item.put("姓名", "小雪");        item.put("性別", "女");        data.add(item);        item = new HashMap<String, Object>();        item.put("姓名", "小明");        item.put("性別", "男");        data.add(item);        listView = new ListView(this);        adapter = new SimpleAdapter(this, data,                android.R.layout.simple_list_item_2, new String[] {"姓名", "性別"},                new int[] {android.R.id.text1, android.R.id.text2});         listView.setAdapter(adapter);         setContentView(listView);         listener = new OnItemClickListener() {            public void onItemClick(AdapterView<?> parent,                    View view, int position, long id) {                Toast.makeText(ActivityList2.this, parent.getItemAtPosition(position).toString()                    + " clicked",Toast.LENGTH_SHORT).show();            }        };        listView.setOnItemClickListener(listener);    }}

API知識點

SimpleAdapter

public class

SimpleAdapter

extends BaseAdapter

implements Filterable

 

SimpleAdapter(Contextcontext, List<? extends Map<String, ?>> data, int resource,String[] from, int[] to)

Constructor

 

 

 

Android常用UI組件 - ListView