项目中要使用viewPager同时要实现动态增加删除的效果。
首先实现viewPager和fragment的嵌套使用,在google的Android开发文档里有现成的例子:地址如下:
https://developer.android.com/reference/android/support/v4/app/FragmentStatePagerAdapter.html
例子里是固定的10个页面,现在开始实现动态增加页面的功能:(先讲过程代码,最后附完整代码)
1.在调用类里面实现一个Fragment列表用于增加、删除Fragment;
private ArrayList<Fragment> fragments = null;
fragments = new ArrayList<>();2.在列表里面添加几个fragment。其中 ArrayListFragment.newInstance()是自定义的一个framgent类,这句话用于new一个新的实例fragment页面
fragments.add(ArrayListFragment.newInstance(1)); fragments.add(ArrayListFragment.newInstance(2)); fragments.add(ArrayListFragment.newInstance(3));3.在自定义的Adaper里面定义保持fragment的list
private ArrayList<Fragment> fragments = null;同时在构造函数里面添加一个ArrayList<Fragment> 的参数,用于把外面的fragment list 传递进来。
4.在调用类添加俩个函数,分别是添加页面和删除页面:添加和删除的原理是,通过改变list里面的fragment内容,并刷新adaper来实现动态增加,删除的功能
public void AddFragment() { fragments.add(ArrayListFragment.newInstance(5)); mAdapter.notifyDataSetChanged(); } public void DelFragment() { fragments.remove(fragments.size()-1); mAdapter.notifyDataSetChanged(); }5.注意事项,要实现这一的功能需要几个注意事项:
(1)自定义的Adapter 要继承自 FragmentStatePagerAdaper
(2)自定义的Adapter 要重写 getItemPosition 函数:
- @Override
- public int getItemPosition(Object object) {
- // TODO Auto-generated method stub
- return PagerAdapter.POSITION_NONE;
- }
http://blog.csdn.net/quanjin24k/article/details/17318151
动手实现了效果,所以总结一下,贴出完整代码,以方便大家快捷的使用:
以下为完整代码:
MainActivity.java
package com.robert.viewpagertest; import android.content.Context; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentStatePagerAdapter; import android.support.v4.app.ListFragment; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ListView; import android.widget.TextView; import java.util.ArrayList; public class MainActivity extends AppCompatActivity { static final int NUM_ITEMS = 10; MyAdapter mAdapter; ViewPager mPager; private ArrayList<Fragment> fragments = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); fragments = new ArrayList<>(); fragments.add(ArrayListFragment.newInstance(1)); fragments.add(ArrayListFragment.newInstance(2)); fragments.add(ArrayListFragment.newInstance(3)); mAdapter = new MyAdapter(getSupportFragmentManager(), fragments); mPager = (ViewPager)findViewById(R.id.pager); mPager.setAdapter(mAdapter); // Watch for button clicks. Button button = (Button)findViewById(R.id.goto_first); button.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { //mPager.setCurrentItem(0); AddFragment(); } }); button = (Button)findViewById(R.id.goto_last); button.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { // mPager.setCurrentItem(NUM_ITEMS-1); DelFragment(); } }); } public void AddFragment() { fragments.add(ArrayListFragment.newInstance(5)); mAdapter.notifyDataSetChanged(); } public void DelFragment() { fragments.remove(fragments.size()-1); mAdapter.notifyDataSetChanged(); } public static class MyAdapter extends FragmentStatePagerAdapter { private ArrayList<Fragment> fragments = null; private Context context; public MyAdapter(FragmentManager fm, ArrayList<Fragment> fragments) { super(fm); //this.context = context; this.fragments = fragments; // notifyDataSetChanged(); } @Override public int getCount() { return fragments.size();//;NUM_ITEMS; } @Override public Fragment getItem(int position) { //return ArrayListFragment.newInstance(position); return fragments.get(position); } @Override public int getItemPosition(Object object) { // TODO Auto-generated method stub return PagerAdapter.POSITION_NONE; } } // public static class MyFragment extends Fragment { // // } //Ctrl + / : to do this public static class ArrayListFragment extends ListFragment { int mNum; /** * Create a new instance of CountingFragment, providing "num" * as an argument. */ static ArrayListFragment newInstance(int num) { ArrayListFragment f = new ArrayListFragment(); // Supply num input as an argument. Bundle args = new Bundle(); args.putInt("num", num); f.setArguments(args); return f; } /** * When creating, retrieve this instance's number from its arguments. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mNum = getArguments() != null ? getArguments().getInt("num") : 1; } /** * The Fragment's UI is just a simple text view showing its * instance number. */ @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View v = inflater.inflate(R.layout.fragment_pager_list, container, false); View tv = v.findViewById(R.id.text); ((TextView)tv).setText("Fragment #" + mNum); return v; } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); setListAdapter(new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, 0)); } @Override public void onListItemClick(ListView l, View v, int position, long id) { Log.i("FragmentList", "Item clicked: " + id); } } }
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:padding="4dip" android:gravity="center_horizontal" android:layout_width="match_parent" android:layout_height="match_parent"> <android.support.v4.view.ViewPager android:id="@+id/pager" android:layout_width="match_parent" android:layout_height="0px" android:layout_weight="1"> </android.support.v4.view.ViewPager> <LinearLayout android:orientation="horizontal" android:gravity="center" android:measureWithLargestChild="true" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_weight="0"> <Button android:id="@+id/goto_first" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="add"> </Button> <Button android:id="@+id/goto_last" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="del"> </Button> </LinearLayout> </LinearLayout>
fragment_pager_list.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@android:drawable/gallery_thumb"> <TextView android:id="@+id/text" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center_vertical|center_horizontal" android:textAppearance="?android:attr/textAppearanceMedium" android:text="hello_world"/> <!-- The frame layout is here since we will be showing either the empty view or the list view. --> <FrameLayout android:layout_width="match_parent" android:layout_height="0dip" android:layout_weight="1" > <!-- Here is the list. Since we are using a ListActivity, we have to call it "@android:id/list" so ListActivity will find it --> <ListView android:id="@android:id/list" android:layout_width="match_parent" android:layout_height="match_parent" android:drawSelectorOnTop="false"/> <!-- Here is the view to show if the list is emtpy --> <TextView android:id="@android:id/empty" android:layout_width="match_parent" android:layout_height="match_parent" android:textAppearance="?android:attr/textAppearanceMedium" android:text="No items."/> </FrameLayout> </LinearLayout>
开发环境为Android Studio 2.2.3 最新版sdk
compileSdkVersion 25
targetSdkVersion 25
源码下载