【控件篇】ListView 模板

Step 1:   毫无疑问，你首先要有一个主界面 （activity_main.xml）

 

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    tools:context=".MainActivity" ><ListView     android:id="@+id/main_listview"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    ></ListView></LinearLayout>

 

这里主要讲述ListView的使用，就不写太多其他的东西了！

 

Step 2:   接下来，你还需要为ListView的子项定义一个布局 （activiaty_main_listitem.xml）

 

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:orientation="horizontal" >        <ImageView         android:id="@+id/user_head_icon"        android:layout_width="50dp"        android:layout_height="50dp"        android:layout_margin="15dp"        />    <RelativeLayout    android:layout_width="match_parent"    android:layout_height="fill_parent"    >        <TextView     android:id="@+id/user_nickname"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:textSize="14sp"    android:textStyle="bold"    android:layout_marginTop="15dp"    />    <TextView     android:id="@+id/user_sign_text"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_below="@id/user_nickname"    android:textSize="12sp"    android:textStyle="bold"    android:layout_marginTop="8dp"    /></RelativeLayout></LinearLayout>

 

Step 3:   接下来就是我们的 MarsterAdapter.java (模板适配器) 啦

 

public abstract class MarsterAdapter<T> extends BaseAdapter{private List<T> list = new ArrayList<T>();private Context context;private int itemViewId;public MarsterAdapter(Context context,int itemViewId,List<T> list){this.context = context;this.itemViewId = itemViewId;this.list = list;}public Context getContext(){return context;}@Overridepublic int getCount() {return list.size();}@Overridepublic T getItem(int position) {return list.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parents) {if(convertView==null){convertView = LayoutInflater.from(context).inflate(itemViewId, null);initItem(position, convertView, parents);}else{reloadItem(position, convertView, parents);}return convertView;}protected abstract void initItem(int position, View convertView, ViewGroup parents) ;protected abstract void reloadItem(int position, View convertView, ViewGroup parents) ;}

Step 4:   好了，模板适配器已经写好了，接下来我们要实现我们的用户列表所用的Adapter（UserAdapter.java）

 

public class UserAdapter extends MarsterAdapter<User>{private UserHolder holder;public UserAdapter(Context context, int itemViewId, List<User> list) {super(context, itemViewId,list);}@Overrideprotected void initItem(int position, View convertView, ViewGroup parents) {// TODO Auto-generated method stubholder = new UserHolder();holder.headIcon = (ImageView) convertView.findViewById(R.id.user_head_icon);holder.nickName = (TextView) convertView.findViewById(R.id.user_nickname);holder.signText = (TextView) convertView.findViewById(R.id.user_sign_text);setHolderView(position, convertView, parents, holder);convertView.setTag(holder);}@Overrideprotected void reloadItem(int position, View convertView, ViewGroup parents) {// TODO Auto-generated method stubholder = (UserHolder) convertView.getTag();setHolderView(position, convertView, parents, holder);}private void setHolderView(int position, View convertView, ViewGroup parents,UserHolder holder){holder.headIcon.setImageDrawable(getContext().getResources().getDrawable(getItem(position).getHeadIcon()));holder.nickName.setText(getItem(position).getNickName());holder.signText.setText(getItem(position).getSignText());}class UserHolder{ImageView headIcon;TextView nickName;TextView signText;}}

Step 5:   最后就是我们的列表界面了 MainActivity.java

 

public class MainActivity extends Activity {private ListView listView;private UserAdapter adapter;private List<User> list;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initViews();initData();}public void initViews(){list = new ArrayList<User>();adapter = new UserAdapter(this, R.layout.activity_mail_listitem, list);listView =  (ListView) findViewById(R.id.main_listview);listView.setAdapter(adapter);}public void initData(){for(int i=0; i<20; i++){User user = new User();user.setHeadIcon(R.drawable.header);user.setNickName("kael"+i);user.setSignText("每天努力一丢丢，成就大牛的人生！"+i);list.add(user);}adapter.notifyDataSetChanged();}}