Fragment的生命周期和相关UI框架搭建

和宿主activity的关系：

Fragment的生命周期和相关UI框架搭建

1. onAttach(Activity) called once the fragment is associated with its activity.
2. onCreate(Bundle) called to do initial creation of the fragment.
3. onCreateView(LayoutInflater, ViewGroup, Bundle) creates and returns the view hierarchy associated with the fragment.
4. onActivityCreated(Bundle) tells the fragment that its activity has completed its own Activity.onCreate().
5. onViewStateRestored(Bundle) tells the fragment that all of the saved state of its view hierarchy has been restored.
6. onStart() makes the fragment visible to the user (based on its containing activity being started).
7. onResume() makes the fragment interacting with the user (based on its containing activity being resumed).

As a fragment is no longer being used, itgoes through a reverse series of callbacks:

1. onPause() fragment is no longer interacting with the user either because its activity is being paused or a fragment operation is modifying it in the activity.
2. onStop() fragment is no longer visible to the user either because its activity is being stopped or a fragment operation is modifying it in the activity.
3. onDestroyView() allows the fragment to clean up resources associated with its View.
4. onDestroy() called to do final cleanup of the fragment's state.
5. onDetach() called immediately prior to the fragment no longer being associated with its activity.

viewpager和fragment的联合使用方式

①向ViewPager中添加fragment。

利用FragmenPagerAdapter:

一、需求：viewpager和fragment连用

二、思路：向viewpager中添加fragment必须用一个集合承载fragment对象，才能将viewpager和fragment绑定在一起实现联动。而且viewpager每次滑动时没必要每次都创建新的fragment对象，采用工厂模式生产fragment对象。

三、步骤：1、生产不同fragment对象

2、创建一个BaseFragment基类用于存储对象

3、自定义FragmentPagerAdapter子类

4、将viewpager和fragment绑定在一起

四、代码：

package cn.banwxf.googlepalay.ui.Fragment;

 

import java.util.HashMap;

import java.util.Map;

 

import android.support.v4.app.Fragment;

import cn.banwxf.googlepalay.ui.Fragment.impl.AppFragment;

importcn.banwxf.googlepalay.ui.Fragment.impl.CategoryFragment;

importcn.banwxf.googlepalay.ui.Fragment.impl.GameFragment;

importcn.banwxf.googlepalay.ui.Fragment.impl.HomeFragment;

import cn.banwxf.googlepalay.ui.Fragment.impl.HotFragment;

importcn.banwxf.googlepalay.ui.Fragment.impl.RecomendFragment;

importcn.banwxf.googlepalay.ui.Fragment.impl.TopicFragment;

 

/**

 * 工厂模式创建fragment页面，因为页面是固定的。

 * 用集合维护页面对象

 *@author banwxf

 */

 

public class FactoryFragment {

         privatestatic  Map<Integer, BaseFragment>map = new HashMap<Integer, BaseFragment>();//因为页面数量固定所以用集合维护，以位置为标识

 

         publicstatic Fragment createFragment(int pos) {

 

                  BaseFragmentfragment = map.get(pos);

                  if(fragment == null) {//只有当没有所需要的对象时才初始化对象

 

                          switch(pos) {

                          case0:

                                   fragment= new HomeFragment();

                                   break;

                          case1:

                                   fragment= new AppFragment();

                                   break;

                          case2:

                                   fragment= new GameFragment();

                                   break;

                          case3:

                                   fragment= new TopicFragment();

                                   break;

                          case4:

                                   fragment= new RecomendFragment();

                                   break;

                          case5:

                                   fragment= new CategoryFragment();

                                   break;

                          case6:

                                   fragment= new HotFragment();

                                   break;

 

                          }

                          //维护对象没必要每次都创建页面对象

                          map.put(pos,fragment);

                  }

                  returnfragment;

         }

}

适配器：

         classMyAdapter extends FragmentPagerAdapter {

 

                  publicMyAdapter(FragmentManager fm) {

                          super(fm);

                  }

 

                  //返回要显示的页面对象

                  @Override

                  publicFragment getItem(int position) {

                          returnFactoryFragment.createFragment(position);//创建指定位置的fragment

                  }

 

                  //数量

                  @Override

                  publicint getCount() {

                          returnmTabNames.length;//页面数量

                  }

 

         }

②向fragment中添加viewpager等基本容器和布局

一、需求：fragment和其他布局和容器连用

二、思路：在fragment的onCreateView(LayoutInflater,ViewGroup, Bundle) 方法中实例化布局，因为有多个界面，需要一个基类，让子类分别去实现不同的布局。

三、步骤：1、写一个抽象的BaseFragment类继承Fragment,重写生命周期方法

2、方法回调

四：、代码：

package cn.banwxf.newsclient.fragment;

 

import android.app.Activity;

import android.app.Fragment;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

 

public abstract class BaseFragment extendsFragment {

         publicActivity mActivity;//这个就是mainActivity

 

         @Override

         publicvoid onCreate(Bundle savedInstanceState) {

                  super.onCreate(savedInstanceState);

                  mActivity= getActivity();// 获取当前fragment所依赖的activity

         }

         //fragment所依赖的activity的oncreate方法执行结束

         @Override

         publicvoid onActivityCreated(Bundle savedInstanceState) {

                  super.onActivityCreated(savedInstanceState);

                  initDate();

         }

         //初始化fragment的布局

         @Override

         publicView onCreateView(LayoutInflater inflater, ViewGroup container,

                          BundlesavedInstanceState) {

                  returninitView();

         }

 

         //必须由子类实现，初始化布局

         publicabstract View initView();

 

         //必须由子类实现，初始化数据

         publicabstract void initDate();

 

}

子类实现两个抽象方法：View view = View.inflate(mActivity, R.layout.fragment_content,null);将view返回即可。