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本文地址: http://blog.csdn.net/caroline_wendy/article/details/21401907
前置项目参见: http://blog.csdn.net/caroline_wendy/article/details/21330733
环境: Android Studio 0.5.1
ArrayAdapter使用泛型(模板)把Adapter视图绑定到一个指定类的对象的数组;
定制ArrayAdapter需要重写getView()方法, 向布局视图分配对象属性;
ToDoList在每一项后面添加时间, 需要创建ToDoItem对象, 使用定制的ArrayAdapter;
步骤:
位置: java->package->ToDoItem
package mzx.spike.todolist.app; import java.text.SimpleDateFormat; import java.util.Date; /** * Created by Administrator on 14-3-17. */ public class ToDoItem { String task; Date created; public String getTask() { return task; } public Date getCreated() { return created; } public ToDoItem(String _task) { this(_task, new Date(java.lang.System.currentTimeMillis())); } public ToDoItem(String _task, Date _created) { task = _task; created = _created; } @Override public String toString() { SimpleDateFormat sdf = new SimpleDateFormat("dd/mm/yy"); String dateString = sdf.format(created); return "(" + dateString + ") " + task; } } 两个私有变量, 存储任务(task)和日期(date), 两种构造方法, 重写了toString方法;
位置: res->layout->todolist_item.xml
1. 使用RelativeLayout(相关)布局;
2. TextView存储日期(date);
3. ToDoListItemView(定制, java)存储任务(task);
4. layout_toLeftOf属性, 表示位于某个视图的左边;
5. fadingEdge标签, 褪去边缘, 遗弃, 被requiresFadingEdge标签代替;
位置: java->package->ToDoItemAdapter
package mzx.spike.todolist.app; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.LinearLayout; import android.widget.TextView; import java.text.SimpleDateFormat; import java.util.Date; import java.util.List; /** * Created by Administrator on 14-3-17. */ public class ToDoItemAdapter extends ArrayAdapter{ int resource; public ToDoItemAdapter(Context context, int _resource, List items) { super(context, _resource, items); this.resource = _resource; } @Override public View getView(int position, View convertView, ViewGroup parent) { LinearLayout toDoView; ToDoItem item = getItem(position); String taskString = item.getTask(); Date createdDate = item.getCreated(); SimpleDateFormat sdf = new SimpleDateFormat("dd/mm/yy"); String dateString = sdf.format(createdDate); if (convertView == null) { toDoView = new LinearLayout(getContext()); String inflater = Context.LAYOUT_INFLATER_SERVICE; LayoutInflater li; li = (LayoutInflater)getContext().getSystemService(inflater); li.inflate(resource, toDoView, true); } else { toDoView = (LinearLayout)convertView; } TextView dateView = (TextView)toDoView.findViewById(R.id.rowDate); TextView taskView = (TextView)toDoView.findViewById(R.id.row); dateView.setText(dateString); taskView.setText(taskString); return toDoView; } }
1. 构造函数, 参数: 视图内容, 资源ID, 数组;
2. 重写getView(), 向布局视图分配对象属性;
3. getItem, 从position获取项目, 第一次更新需要填充视图, 之后转换即可;
4. 给相应的属性复制, 从视图中找到资源引用(findViewById), 给资源赋值;
5. 返回视图;
位置: java->package->ToDoListActivity
package mzx.spike.todolist.app; import android.app.FragmentManager; import android.os.Bundle; import android.support.v7.app.ActionBarActivity; import android.view.Menu; import android.view.MenuItem; import java.util.ArrayList; public class ToDoListActivity extends ActionBarActivity implements NewItemFragment.OnNewItemAddedListener { //使用ToDoItem对象代替String private ToDoItemAdapter aa; private ArrayList toDoItems; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_to_do_list); //获得fragment的引用 FragmentManager fm = getFragmentManager(); ToDoListFragment toDoListFragment = (ToDoListFragment)fm.findFragmentById(R.id.ToDoListFragment); toDoItems = new ArrayList(); int resID = R.layout.todolist_item; //三个参数 aa = new ToDoItemAdapter(this, resID, toDoItems); toDoListFragment.setListAdapter(aa); } //重写了接口的方法 public void onNewItemAdded(String newItem) { ToDoItem newToDoItem = new ToDoItem(newItem); toDoItems.add(0, newToDoItem); aa.notifyDataSetChanged(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.to_do_list, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } } 替换String为ToDoItem, 替换ArrayAdapter<>为ToDoItemAdapter;
代码: http://download.csdn.net/detail/u012515223/7054943
