ToDoList(fragment) 详解
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本文地址: http://blog.csdn.net/caroline_wendy/article/details/21246963
ToDoList做为Android的经典练习, 参考: http://blog.csdn.net/caroline_wendy/article/details/21223995
Fragment(碎片) 可以灵活地从一个活动的Activity上添加或删除Fragment, 有良好的用户体验;
下面是Fragment的具体设计:
1. 创建new_item_fragment的资源文件:
位置: res->new_item_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<EditText xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/myEditText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/addItemHint"
android:contentDescription="@string/addItemContentDescription"
/>
包含一个EditText控件;
2. 创建NewItemFragment的逻辑实现:
位置: java->package->NewItemFragment.java
package mzx.spike.todolist.app;
import android.app.Activity;
import android.app.Fragment;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
/**
* Created by C.L.Wang on 14-3-14.
*/
public class NewItemFragment extends Fragment{
private OnNewItemAddedListener onNewItemAddedListener;
//监听事件
public interface OnNewItemAddedListener {
public void onNewItemAdded(String newItem);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.new_item_fragment, container, false);
final EditText myEditText = (EditText)view.findViewById(R.id.myEditText);
//监听事件
myEditText.setOnKeyListener(new View.OnKeyListener() {
@Override
public boolean onKey(View view, int i, KeyEvent keyEvent) {
if (keyEvent.getAction() == KeyEvent.ACTION_DOWN)
if ((i == KeyEvent.KEYCODE_DPAD_CENTER) ||
(i == KeyEvent.KEYCODE_ENTER)) {
String newItem = myEditText.getText().toString();
onNewItemAddedListener.onNewItemAdded(newItem);
myEditText.setText("");
return true;
}
return false;
}
});
return view;
}
//绑定到Activity
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
onNewItemAddedListener = (OnNewItemAddedListener)activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + " must implement OnNewItemAddedListener");
}
}
}
详解:
1. 继承Fragment类;
2. 监听接口(interface OnNewItemListener), 包含一个监听方法(onNewItemAdded), 然后实现一个实例;
3. 创建视图(onCreateView), 需要返回一个视图(View);
4. 填充一个视图, 调用inflater.inflate()函数, 绑定fragment的资源文件;
5. 获得控件的引用, view.findViewById(), 得到myEditText的引用;
6. 监听事件, 监听myEditText的输入内容, 传递给接口的内容(new Item);
7. 使用onAttach()函数, 绑定Acitivity之后, 获得activity的引用;
3. 创建ToDoListFragment的逻辑实现:
位置: java->package->ToDoListFragment.java
package mzx.spike.todolist.app;
import android.app.ListFragment;
/**
* Created by C.L.Wang on 14-3-14.
*/
public class ToDoListFragment extends ListFragment{
}
继承ListFragment;
4. 创建activity_to_do_list资源文件, 即Activity资源文件:
位置: res->layout->activity_to_do_list.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="mzx.spike.todolist.app.ToDoListActivity">
<fragment android:name="mzx.spike.todolist.app.NewItemFragment"
android:id="@+id/NewItemFragment"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/addItemHint"
android:contentDescription="@string/addItemContentDescription"
/>
<fragment android:name="mzx.spike.todolist.app.ToDoListFragment"
android:id="@+id/ToDoListFragment"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
LinearLayout包含两个fragment结点, 需要提供android:name的参数, 实现;
5. 创建ToDoListActivityt的逻辑实现, 即Activity的逻辑实现:
位置: java->package->ToDoListActivityt.java
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 android.widget.ArrayAdapter;
import java.util.ArrayList;
public class ToDoListActivity extends ActionBarActivity implements NewItemFragment.OnNewItemAddedListener {
private ArrayAdapter<String> aa;
private ArrayList<String> 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<String>();
//三个参数
aa = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, toDoItems);
toDoListFragment.setListAdapter(aa);
}
//重写了接口的方法
public void onNewItemAdded(String newItem) {
toDoItems.add(newItem);
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);
}
}
详解:
1. 继承监听接口(OnNewItemAddedListener);
2. ArrayList类型数据, 和适配器(ArrayAdapter);
3. 通过findFragmentById(), 获得ToDoListFragment的引用;
4. 把toDoItem绑定适配器, ToDoListFragment设置适配器(setListAdapter);
5. 实现接口的方法, 传递至toDoItems, 通知适配器更改(notifyDataSetChanged);
6. 执行程序:
其他文件参考: http://blog.csdn.net/caroline_wendy/article/details/21223995
下载地址: http://download.csdn.net/detail/u012515223/7042137