当我们使用activity加fragment的时候,每个界面都要建立一个fragment,每个fragment里面都要重写onCreate(),onCreateView(),onActivityCreated(),方法,我们新建一个基类BaseFragment来重写这些方法
BaseFragment需要定义一个抽象方法initView(),用来初始化View对象,需要子类去实现,我们父类把LayoutInflater对象传进去
BaseFragment需要定义一个抽象方法initData(),用来初始化数据,需要子类去实现
package com.qingguow.news.fragment;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* 基础类
* @author taoshihan
*
*/
public abstract class BaseFragment extends Fragment {
public Context context;
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onActivityCreated(savedInstanceState);
initData(savedInstanceState);
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
context=getActivity();
}
@Override
@Nullable
public View onCreateView(LayoutInflater inflater,
@Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view=initView(inflater);
return view;
}
/**
* 初始化View对象
* @param inflater
* @return
*/
public abstract View initView(LayoutInflater inflater);
/**
* 初始化数据
* @param Bundle
* @return
*/
public abstract void initData(Bundle savedInstanceState);
}
主Fragment里实现Banner轮播
在fragment_index.xml布局文件中添加节点<android.support.v4.view.ViewPager />
获取ViewPager对象,通过findViewById()方法
调用ViewPager对象的setAdapter()方法,设置适配器,参数:PagerAdapter对象
使用匿名内部类的方式实现抽象方法,getCount(),isViewFromObject(),instantiateItem(),destroyItem()
重写getCount()方法,返回轮播的个数
重写isViewFromObject()方法,返回布尔值,
重写instantiateItem()方法,将当前view对象添加到ViewGroup对象,返回当前对象
重写destroyItem()方法,从当前container中删除指定位置(position)的View
package com.qingguow.news.fragment;
import java.util.ArrayList;
import java.util.List;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.qingguow.news.R;
/**
* 首页
* @author taoshihan
*
*/
public class IndexFragment extends BaseFragment {
private List<View> banners;
@Override
public View initView(LayoutInflater inflater) {
View view=inflater.inflate(R.layout.fragment_index, null);
//banner部分
banners=new ArrayList<>();
TextView tv=new TextView(context);
tv.setText("测试");
banners.add(tv);
TextView tv2=new TextView(context);
tv2.setText("测试2");
banners.add(tv2);
ViewPager vp=(ViewPager) view.findViewById(R.id.vp_banner);
vp.setAdapter(new PagerAdapter(){
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView(banners.get(position));
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
container.addView(banners.get(position));
return banners.get(position);
}
@Override
public int getCount() {
return banners.size();
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0==arg1;
}
});
return view;
}
@Override
public void initData(Bundle savedInstanceState) {
// TODO Auto-generated method stub
}
}