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：wangkuifeng0118@126.com"}; 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", "wangkuifeng0118@126.com"}; 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","wangkuifeng0118@126.com"}; 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。