Android适配器Adapter学习

在开发中我们需要绑定一些数据展现到桌面上，这是就需要AdapterView。AdapterView是ViewGroup的子类，它决定了怎么展现视图通过Adapter来绑定特殊的数据类型。 AdapterView是非常有帮助的当你展现数据在你的布局中。Gallery,ListView和 Spinner是AdapterView的子类。

下面看一下AdapterView的结构图：

然后再看一下Adapter的结构图：

上面已经充分展现了他们的子类和父类的基础关系。

下面我们看一个ListViewDemo的例子：

先来看一个简单的adapter的例子：

public class SimpleList extends ListActivity {
    private String[] mListString={"姓名：王魁锋","性别：男","年龄：23",
    		"居住地：上海市普陀区","邮箱：[e-mail]"};
	private ListView mListView=null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		mListView=this.getListView();
		setListAdapter(new ArrayAdapter<String>(this,
			android.R.layout.simple_list_item_1,mListString));
		mListView.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				// TODO Auto-generated method stub
			Toast.makeText(SimpleList.this, "你选择了："+mListString[position], 1).show();
			}
		});
	}

这里用到了系统定义好的适配模式，当然这只能用来简单的数据适配，下面看一下效果：

接下来看一个稍微复杂点的，SimpleAdapter怎么适配：

public class IconList extends ListActivity {

	 private String[] mListTitle = { "姓名", "性别", "年龄", "居住地","邮箱"};  
	    private String[] mListStr = { "王魁锋", "男", "23", "上海市普陀区",  
	        "[e-mail]"};  
	    ListView mListView = null;  
	    ArrayList<Map<String,Object>> mData= new ArrayList<Map<String,Object>>();;  
	  
	    @Override
	    protected void onCreate(Bundle savedInstanceState) {
	    	// TODO Auto-generated method stub
	    	 mListView = getListView();  
		        
	 	    int lengh = mListTitle.length;  
	 	    for(int i =0; i < lengh; i++) {  
	 	        Map<String,Object> item = new HashMap<String,Object>();  
	 	        item.put("image", R.drawable.portrait);  
	 	        item.put("title", mListTitle[i]);  
	 	        item.put("text", mListStr[i]);  
	 	        mData.add(item);   
	 	    }  
	 	    SimpleAdapter adapter = new SimpleAdapter(this,mData,R.layout.iconlist,  
	 	        new String[]{"image","title","text"},new int[]{R.id.image,R.id.title,R.id.text});  
	 	        setListAdapter(adapter);  
	 	    mListView.setOnItemClickListener(new OnItemClickListener() {  
				@Override
				public void onItemClick(AdapterView<?> parent, View view,
						int position, long id) {
					// TODO Auto-generated method stub
					 Toast.makeText(IconList.this,"您选择了标题：" + mListTitle[position] + "    内容："+mListStr[position], Toast.LENGTH_LONG).show();  
				 	 
				}  
	 	    });  
	    	super.onCreate(savedInstanceState);
	    }
}

上面的数据可以是同数据库读取的也可以是从网络获取的，这里不做过多介绍,看下效果：

哈哈 看起来美观了些，如果要做更复杂的布局，哪就要用BaseAdapter了。先看一下布局文件：

<?xml version="1.0" encoding="utf-8"?>  
  
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:layout_width="fill_parent" android:layout_height="wrap_content">  
    <ImageView android:id="@+id/color_image"  
        android:layout_width="wrap_content" android:layout_height="fill_parent"  
        android:layout_alignParentTop="true" android:layout_alignParentBottom="true"  
        android:adjustViewBounds="true"  
        android:padding="2dip" />  
    <TextView android:id="@+id/color_title"  
        android:layout_width="fill_parent" android:layout_height="wrap_content"  
        android:layout_toRightOf="@+id/color_image"  
        android:layout_alignParentTop="true"  
        android:layout_alignParentRight="true" android:singleLine="true"  
        android:ellipsize="marquee"   
        android:textSize="15dip"  />  
    <TextView android:id="@+id/color_text"  
        android:layout_width="fill_parent" android:layout_height="wrap_content"  
        android:layout_toRightOf="@+id/color_image"  
        android:layout_below="@+id/color_title"  
        android:layout_alignParentBottom="true"  
        android:layout_alignParentRight="true"   
        android:singleLine="true"  
        android:ellipsize="marquee"   
        android:textSize="20dip" />  
</RelativeLayout>  

下面是核心代码：

public class ColorList extends ListActivity {
	 private String[] mListTitle = { "姓名", "性别", "年龄", "居住地","邮箱"};  
	 private String[] mListText={"王魁锋","男","23","上海市普陀区","[e-mail]"};
	 private ListView mListView=null;
	 private MyListAdapter myAdapter=null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		 mListView=this.getListView();
		 myAdapter=new MyListAdapter(this);
		 this.setListAdapter(myAdapter);
		 
		 mListView.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				// TODO Auto-generated method stub
				View v=parent.getChildAt(position);
				v.setBackgroundColor(Color.RED);
				Toast.makeText(ColorList.this, "你选择了 "+mListText[position], 1).show();
			}
		});
		super.onCreate(savedInstanceState);
	}
	private class MyListAdapter extends BaseAdapter{
        private Context mContext;
		private int[] colors=new int[]{0xff626569,0xff4f5257 };
		 public MyListAdapter(Context context){
			 mContext=context;
		 }
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return mListText.length;
		}

		@Override
		public Object getItem(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		@Override
		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			ImageView image=null;
			TextView title=null;
			TextView  content=null;
			if(convertView==null){
				convertView=LayoutInflater.from(mContext).inflate(R.layout.colorlist, null);
				image=(ImageView) convertView.findViewById(R.id.color_image);
				title=(TextView) convertView.findViewById(R.id.color_title);
				content=(TextView) convertView.findViewById(R.id.color_text);
			}
			int colorPos=position%colors.length;
			convertView.setBackgroundColor(colors[colorPos]);
			title.setText(mListTitle[position]);
			content.setText(mListText[position]);
			image.setImageResource(R.drawable.portrait);
			
			return convertView;
		}
		
	}
}

BaseAdapter可以让我们做比较复杂的布局，只要在xml文件中设置好布局格式，在getView中分别取出放入相应的值就可以了。下面看一些效果：




还有一些SpinnerAdapter和SimpleCursorAdapter等系统自带的适配器，都是比较简单的，可以看下API自行练习一下，这里特别说明一下，从数据库里取出的数据最好直接放入SimpleCursorAdapter很方便的。