android权威编程指南学习笔记

activity中的代码基本都转移到Fragment里了 这样真的好么

1. 首先创建模型类，根据需要添加数据集中存储池来存储模型对象

（如使用支持存放指定数据类型对象的Java有序数组类，ArrayList<E>， 具有获取、新增、删除数组中元素的方法。）

public class DemosLab {//有序组成员变量private ArrayList<Demo> mDemos;//静态对象private static DemosLab sDemosLab;private Context mAppContext;private DemosLab(Context appContext){mAppContext = appContext;mDemos = new ArrayList<Demo>();Demo demo = new Demo();demo.setName("Service");demo.setDate("2015/9/9"); demo.setDescription("学习Service");demo.setFinished(false);mDemos.add(demo);}public ArrayList<Demo> getDemos(){return mDemos;}public Demo getDemo(String name){for(Demo demo : mDemos){if(demo.getName().equals(name))  return demo;}return null;}public static DemosLab get(Context c){if(sDemosLab == null){sDemosLab = new DemosLab(c.getApplicationContext());}return sDemosLab;}    }

2.继承抽象自定义Activity

 目前仅新增了添加Fragment方法，activity布局名默认为activity_main

public abstract class SingleFragmentActivity extends FragmentActivity//抽象方法 提供Fragment实例protected abstract android.app.Fragment createFragment();@Override    protected void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);       setContentView(R.layout.activity_main);              if (savedInstanceState == null) {            getFragmentManager().beginTransaction()            //抽象方法 也就是模板，具体实现具体对待                    .add(R.id.container,createFragment())                    .commit();        }   }  }

3.继承抽象自定义Fragment（继承ListFragment）

新增添加Fragment参数的方法、选项菜单（监听）

public class DemosListFragment extends ListFragment {private static final int REQUESR_DEMOSLIST = 1;private ArrayList<Demo> mDemos;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);getActivity().setTitle(R.string.app_name);//此项根据需要设置是否保留Fragment      setRetainInstance(true);//设置此项才可以在fragment中正确使用选项菜单setHasOptionsMenu(true);//使用DemosLab的静态方法获取其实例进而获得demos数组mDemos = DemosLab.get(getActivity()).getDemos();//使用自定义Adapter填充数据DemoAdapter adapter = new DemoAdapter(mDemos);setListAdapter(adapter);}//状态保存@Overridepublic void onSaveInstanceState(Bundle outState) {// TODO Auto-generated method stubsuper.onSaveInstanceState(outState);//选项菜单@Overridepublic void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {// TODO Auto-generated method stubsuper.onCreateOptionsMenu(menu, inflater);inflater.inflate(R.menu.main, menu);}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {if(item.getItemId() == android.R.id.home){Toast.makeText(getActivity(), "返回"+item.getItemId(),Toast.LENGTH_SHORT).show();try {Thread.sleep(2000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}NavUtils.navigateUpFromSameTask(getActivity());}Toast.makeText(getActivity(), ""+item.getItemId(),Toast.LENGTH_SHORT).show();// 返回true表明已完成处理return true;}//覆盖Fragment.onActivityForResult方法从被启动activiy获取结果@Overridepublic void onActivityResult(int requestCode, int resultCode, Intent data) {if(requestCode == REQUESR_DEMOSLIST){Toast.makeText(getActivity(), "got result:"+resultCode, Toast.LENGTH_SHORT).show();}}//刷新列表项@Overridepublic void onResume() {// TODO Auto-generated method stubsuper.onResume();((DemoAdapter)getListAdapter()).notifyDataSetChanged();}//Toast便捷方法protected void toast(Context context,String text) {Toast.makeText(context, text, Toast.LENGTH_SHORT).show();}//警告对话框便捷方法protected void alert(String content) {AlertDialog.Builder builder = new AlertDialog.Builder(getActivity()).setTitle("提示").setMessage(content);builder.setPositiveButton("确定",new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialog, int which) {mtoast(getActivity(), ""+which);});builder.create().show();}

4.自定义Adapter

private class DemoAdapter extends ArrayAdapter<Demo>{public DemoAdapter(ArrayList<Demo> demos) {super(getActivity(),0,demos);}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {//列表优化，convertView是刚刚被销毁的视图if(convertView == null){convertView = getActivity().getLayoutInflater().inflate(R.layout.list_item_demo, null);}Demo demo = getItem(position);TextView tv1 = (TextView) convertView.findViewById(R.id.textView1);TextView tv2 = (TextView) convertView.findViewById(R.id.textView2);CheckBox finishedBox = (CheckBox) convertView.findViewById(R.id.checkBox1);;tv1.setText(demo.getName()+"\n"+demo.getDescription());tv2.setText(demo.getDate());finishedBox.setChecked(demo.isFinished());return convertView;}}

//常用功能

1.使用dialog

//TODO

2.Fragment/Activity间传递数据

 //Activity.onActivityForResult在子Activity销毁后由ActivityManager自动调用的父类方法 随后FragmenManager会调用对应Fragment.onActivityResult

而下面两个Fragment间传递数据则要自己调用Fragment.onActivityResult()方法

activity间：  Activity.startActivityForResult & Activity.onActivityForResult ------Activity.setResult(int resultcode)

//从Fragment中启动Activity，使用Fragment.startActivityForResult()

基于fragment的activity间：目标activity接受父activity的数据后调用托管Fragment的newInstance静态方法 其中有Fragment..setArguments(Bundle)  -------  getArguments()

Activity.setResult(int resultcode)

//与Activity间的关联的区别：

对于activity间的回传，我们调用startActivityForResult（）方法，ActivityManager负责跟踪记录父子Activity见得关系，当子Activity返回数据被销毁之后，ActivityManager知道应该把数据返回给谁。

      //而此处我们需要为要返回数据的Fragment指定目标Fragment

FragmentManager可使用该请求码得知是哪一个在返回数据

一般此项在目标Fragment中进行设置。。。。。。。。。。

同一Activity托管的Fragment间：在Fragment中调用目标Fragment的newInstance方法传去参数（同上），------- XFragment.setTargetFragment(TFragment .this, RequestCode)

fragment.getTargetFragment().onActivityResult(getTargetRequestCode(),resultCode,intent);

3.fragment的保留

设置fragment的属性值---->在onCreate方法中调用setRetainInstance(true);其默认值是false；

表明其不会被保留。所以当设备旋转时fragment会随托管activity一起被销毁并重建，设为true则会被一直保留并在需要时原封不动的传递给新的activity。（实际情况是：销毁和重建fragment视图，但保留fragment自身）。

//TODO fragment生命周期图

保留fragment只能应对短时间的像设备旋转这样的销毁，若长久离开进程关闭时，activity、fragment（无论保留与否）都会消亡，而activity记录不会，因此应该覆盖Fragment.onSaveInstanceState();

4.操作栏

1)选项菜单（在Fragment中创建 同在Activity）

a.定义选项菜单的XML文件 res/menu       id,icon,title,showAsAction(ifRoom|withText|always|never)

b.setHasOptionsMenu(true) 通知FragmentManager应该接受Activity的方法调用指令

c.重写

@Overridepublic void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {// TODO Auto-generated method stubsuper.onCreateOptionsMenu(menu, inflater);inflater.inflate(R.menu.main, menu);}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {if(item.getItemId() == android.R.id.home){Toast.makeText(getActivity(), "返回"+item.getItemId(),Toast.LENGTH_SHORT).show();NavUtils.navigateUpFromSameTask(getActivity());}Toast.makeText(getActivity(), ""+item.getItemId(),Toast.LENGTH_SHORT).show();// 返回true表明已完成处理return true;}

2)层级式导航（Ancestral navigation）

使操作栏上的应用图标具有向上按钮的功能。

a.调用setDisplayHomeAsUpEnable(true)设置Fragment属性

if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB){if(NavUtils.getParentActivityName(getActivity())!=null){getActivity().getActionBar().setDisplayHomeAsUpEnabled(true);}}

b.在AndroidManifest.xml中为各个子Activity添加新的meta-data属性，指定其父类

eg.

<meta-data android:name="android.support.PARENT_ACTIVITY"       android:value=".MainActivity"/><intent-filter >

c.监听（相当于一个选项菜单项，在选项菜单监听器中增加一项判断即可）

@Overridepublic boolean onOptionsItemSelected(MenuItem item) {if(item.getItemId() == android.R.id.home){if(NavUtils.getParentActivityName(getActivity())!=null){NavUtils.navigateUpFromSameTask(getActivity());}// 返回true表明已完成处理return true;}

5.上下文菜单与上下文操作模式

1）浮动上下文：（注册在ListView）

首先在onCreateView方法中向组件注册上下文菜单

Fragment. registerForContextMenu(listView);

@Overridepublic void onCreateContextMenu(ContextMenu menu, View v,ContextMenuInfo menuInfo) {super.onCreateContextMenu(menu, v, menuInfo);getActivity().getMenuInflater().inflate(R.menu.demo_list_item_context, menu);}@Overridepublic boolean onContextItemSelected(MenuItem item) {AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();int position = info.position;DemoAdapter adapter = (DemoAdapter) getListAdapter();Demo demo = adapter.getItem(position);switch (item.getItemId()) {case R.id.delete:break;case R.id.cancle:break;default:break;}return true;}

2)上下文操作模式：（ListView多选模式）

1.向ListView注册：listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);

2.实现AbsListView.MultiChoiceModeListener接口的监听器

listView.setMultiChoiceModeListener(new MultiChoiceModeListener() {...}

包含以下回调方法，视图在选中或撤销选中时会触发它

@Override
public void onItemCheckedStateChanged(ActionMode mode, int position,
long id, boolean checked) {
// TODO Auto-generated method stub
}

MultiChoiceModeListener实现了另一个接口，即ActionMode.Callback，必须实现以下四个方法。

public boolean onPrepareActionMode(ActionMode mode, Menu menu) {}public void onDestroyActionMode(ActionMode mode) {}public boolean onCreateActionMode(ActionMode arg0, Menu arg1) {}public boolean onActionItemClicked(ActionMode arg0, MenuItem arg1) {}

在Fragment的onCreateView方法中注册：

if(Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB)registerForContextMenu(listView);<span style="white-space:pre"></span>//这是注册浮动上下文菜单（无需手动绑定监听器）else {listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);<span style="white-space:pre"></span>//这是注册多选上下文操作模式listView.setMultiChoiceModeListener(new MultiChoiceModeListener(){实现上面的五个方法}

主要是这两个方法：

<span style="white-space:pre">@Override<span style="white-space:pre"></span>public boolean onCreateActionMode(ActionMode arg0, Menu arg1) {<span style="white-space:pre"></span>MenuInflater inflater = arg0.getMenuInflater();<span style="white-space:pre"></span>inflater.inflate(R.menu.demo_list_item_context, arg1);<span style="white-space:pre"></span>return true;<span style="white-space:pre"></span>}<span style="white-space:pre"></span><span style="white-space:pre"></span>@Override<span style="white-space:pre"></span>public boolean onActionItemClicked(ActionMode arg0, MenuItem arg1) {<span style="white-space:pre"></span><span style="white-space:pre"></span>switch (arg1.getItemId()) {<span style="white-space:pre"></span>case R.id.delete:<span style="white-space:pre"></span>new AlertDialog.Builder(getActivity()).setMessage("deleted!").setPositiveButton("确定", null).create().show();<span style="white-space:pre"></span>break;<span style="white-space:pre"></span>case R.id.cancle:<span style="white-space:pre"></span>new AlertDialog.Builder(getActivity()).setMessage("cancled!").setPositiveButton("确定", null).create().show();<span style="white-space:pre"></span>break;<span style="white-space:pre"></span>default:<span style="white-space:pre"></span>break;<span style="white-space:pre"></span>}<span style="white-space:pre"></span>return true;<span style="white-space:pre"></span>}<span style="white-space:pre"></span></span>

改变已激活视图的显示背景：

使用state list drawable

在drawable目录下创建以selector为根元素的xml文件：

<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="http://schemas.android.com/apk/res/android">    <item android:state_activated="true"        android:drawable="@android:color/darker_gray"/></selector>

设置列表项背景引用该资源：

android:background="@drawable/bgc_act"

····················································································································

其他视图上的上下文操作模式：

步骤如下---

1.设置一个实现View.OnLongClickListener接口的监听器

2.在监听器实现体内调用Activity.startActionMode(...)方法创建一个ActionMode实例  .实现AbsListView.MultiChoiceModeListener接口的监听器ActionMode实例是自动创建的

·

3.创建一个实现ActionMode.Callback接口的匿名实现作为参数传入startActionMode

eg：

TextView tv = (TextView) view.findViewById(R.id.text1);tv.setOnLongClickListener(new OnLongClickListener() {@Overridepublic boolean onLongClick(View v) {getActivity().startActionMode(new ActionMode.Callback() {@Overridepublic boolean onPrepareActionMode(ActionMode mode, Menu menu) {// TODO Auto-generated method stubreturn false;}@Overridepublic void onDestroyActionMode(ActionMode mode) {// TODO Auto-generated method stub}@Overridepublic boolean onCreateActionMode(ActionMode mode, Menu menu) {mode.getMenuInflater().inflate(R.menu.demo_list_item_context, menu);return true;}@Overridepublic boolean onActionItemClicked(ActionMode mode, MenuItem item) {Toast.makeText(getActivity(), "ok", Toast.LENGTH_SHORT).show();return true;}});return false;}});

6.存储与加载本地文件