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。