android 中的 ViewPager+ Fragment

時間 2019-12-05

標籤 android viewpager fragment 欄目 Android 简体版

原文原文鏈接

android的Viewpager 的各類常常的用法，朋友問我要過，因此就稍微總結一下，android

ViewPager + Fragment 常常用到代碼是從 actionbarsherlock 中提取出來的，這個效果都知道是滑動來切換的。直接上代碼了web

在這裏簡單說明一下 FragmentStatePagerAdapter 和 FragmentPagerAdapteride

2個adapter 佈局

第一種 fragment狀態adapter - 在當前只會存在前1個fragment 當前 fragment 和下1個 fragment 其餘銷燬，適合加載多數據this

第二種 FragmentPagerAdapter - 所有存在，因此不太適合加載大量的數據如圖片什麼的，很容易內存溢出。spa

工程結構：orm

1. activity adapter 在一塊兒（static類型的 Fragment）xml

public class ViewPageFragment extends FragmentActivity { 圖片
//這個是有多少個 fragment頁面內存
static final int NUM_ITEMS = 5;
private MyAdapter mAdapter;
private ViewPager mPager;
private int nowPage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.pagers_fragment_main);
mAdapter = new MyAdapter(getSupportFragmentManager() );
mPager = (ViewPager)findViewById(R.id.mypagers_pager);
mPager.setAdapter(mAdapter);
}
/**
* 有狀態的，只會有前3個存在其餘銷燬，前1個，中間，下一個
*/
public static class MyAdapter extends FragmentStatePagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
@Override
public int getCount() {
return NUM_ITEMS;
}
//獲得每一個item
@Override
public Fragment getItem(int position) {
return ArrayFragment.newInstance(position);
}
// 初始化每一個頁卡選項
@Override
public Object instantiateItem(ViewGroup arg0, int arg1) {
// TODO Auto-generated method stub
return super.instantiateItem(arg0, arg1);
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
System.out.println( "position Destory" + position);
super.destroyItem(container, position, object);
}
}
/**
* 無狀態的會所有加載着，這個適合少許的特別多的圖片啊啥的仍是用 FragmentStatePagerAdapter
* @author lilei
*/
// public static class MyAdapter extends FragmentPagerAdapter {
// public MyAdapter(FragmentManager fm ) {
// super(fm);
//
// }
//
// @Override
// public int getCount() {
// return NUM_ITEMS;
// }
//
// @Override
// public Fragment getItem(int position) {
// // 返回相應的 fragment
// return ArrayFragment.newInstance(position);
// }
//
// @Override
// public void destroyItem(ViewGroup container, int position, Object object) {
// System.out.println( "position Destory" + position);
// super.destroyItem(container, position, object);
// }
// }
/**
* 全部的每一個Fragment
*/
public static class ArrayFragment extends Fragment {
int mNum;
static ArrayFragment newInstance(int num) {
ArrayFragment array= new ArrayFragment();
Bundle args = new Bundle();
args.putInt("num", num);
array.setArguments(args);
return array;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mNum = getArguments() != null ? getArguments().getInt("num") : 1;
System.out.println("mNum Fragment create ="+ mNum);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
System.out.println("onCreateView = ");
//在這裏加載每一個 fragment的顯示的 View
View v = null;
if(mNum == 0){
v = inflater.inflate(R.layout.pagers_fragment1, container, false);
((TextView)v.findViewById(R.id.textView1)).setText(mNum+ "= mNum");
}else if(mNum == 1){
v = inflater.inflate(R.layout.pagers_fragment1, container, false);
((TextView)v.findViewById(R.id.textView1)).setText(mNum+ "= mNum");
}else if(mNum == 2){
v = inflater.inflate(R.layout.pagers_fragment1, container, false);
((TextView)v.findViewById(R.id.textView1)).setText(mNum+ "= mNum");
}else{
v = inflater.inflate(R.layout.pagers_fragment1, container, false);
((TextView)v.findViewById(R.id.textView1)).setText(mNum+ "= mNum");
}
return v;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
System.out.println("onActivityCreated = ");
super.onActivityCreated(savedInstanceState);
}
@Override
public void onDestroyView(){
System.out.println(mNum + "mNumDestory");
super.onDestroyView();
}
@Override
public void onDestroy(){
super.onDestroy();
}
}
}

2. 和 1也沒什麼太大區別（箇中用處看我的了）

public class ViewPageFragmentCS extends FragmentActivity {
//這個是有多少個 fragment頁面
private MyAdapter mAdapter;
private ViewPager mPager;
private List<Entity> list = new ArrayList<ViewPageFragmentCS.Entity>();;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.pagers_fragment_main);
for (int i = 0; i < 7 ; i++) {
Entity ee = new Entity();
ee.name = "ll"+ i;
ee.age = ""+ i;
list.add(ee);
}
mAdapter = new MyAdapter(getSupportFragmentManager(),list);
mPager = (ViewPager)findViewById(R.id.mypagers_pager);
mPager.setAdapter(mAdapter);
}
private class Entity{
public String name;
public String age;
}
// 在這裏你能夠傳 list<Fragment> 也能夠傳遞 list<Object>數據
public class MyAdapter extends FragmentStatePagerAdapter {
List<Entity> list_ee;
public MyAdapter(FragmentManager fm, List<Entity> ee) {
super(fm);
this.list_ee = ee ;
}
@Override
public int getCount() {
return list_ee.size();
}
// 初始化每一個頁卡選項
@Override
public Object instantiateItem(ViewGroup arg0, int position) {
ArrayFragment ff = (ArrayFragment)super.instantiateItem(arg0, position);
ff.setThings(list_ee.get(position),position);
return ff;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
System.out.println( "position Destory" + position);
super.destroyItem(container, position, object);
}
@Override
public Fragment getItem(int arg0) {
// TODO Auto-generated method stub
return new ArrayFragment();
}
}
/**
* 全部的每一個Fragment
*/
public class ArrayFragment extends Fragment {
private Entity ee;
private int position;
public void setThings(Entity ee,int position){
this.ee =ee ;
this.position = position;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
System.out.println("onCreateView = ");
//在這裏加載每一個 fragment的顯示的 View
View v = inflater.inflate(R.layout.pagers_fragment1, container, false);
((TextView)v.findViewById(R.id.textView1)).setText(ee.name+ "= ee.Name -=age"+ ee.age);
return v;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
System.out.println("onActivityCreated = ");
super.onActivityCreated(savedInstanceState);
}
@Override
public void onDestroyView(){
System.out.println("onDestroyView = "+ position);
super.onDestroyView();
}
@Override
public void onDestroy(){
System.out.println("onDestroy = "+ position);
super.onDestroy();
}
}
}