ViewPager的简单例子

这个例子是按照官网上的例子写的，有点抄袭的嫌疑，但是自己单独写一下会加深自己的印象。

首先是MainAcitivity.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity">    <android.support.v4.view.ViewPager        android:translationZ="10dp"        android:elevation="10dp"        android:id="@+id/view_pager"        android:layout_width="match_parent"        android:layout_height="0dp"        android:layout_weight="1" />    <LinearLayout        android:layout_width="match_parent"        android:layout_height="0dp"        android:layout_weight="1"        android:gravity="center"        android:orientation="vertical">        <Button            android:id="@+id/go_to_first_item"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_margin="10dp"            android:padding="10dp"            android:text="@string/first"            android:textAllCaps="false" />        <Button            android:id="@+id/go_to_last_item"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_margin="10dp"            android:padding="10dp"            android:text="@string/last"            android:textAllCaps="false" />    </LinearLayout></LinearLayout>

布局很简单，就是一个ViewPager加上一个LinearLayout

然后ViewPager中的item的布局，这里的ViewPager使用的adapter是FragmentStatePagerAdatper

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical">    <TextView        android:id="@+id/text"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center_vertical|center_horizontal"        android:text="@string/hello_world"        android:textAppearance="?android:attr/textAppearanceMedium" />    <FrameLayout        android:layout_width="match_parent"        android:layout_height="0dp"        android:layout_weight="1">        <ListView            android:id="@android:id/list"            android:layout_width="match_parent"            android:layout_height="match_parent" />        <TextView            android:id="@android:id/empty"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:text="No items."            android:textAppearance="?android:attr/textAppearanceMedium" />    </FrameLayout></LinearLayout>

然后是MainAcitivity的代码：

package com.example.crazykids.customsizeviewpager;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.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;public class MainActivity extends AppCompatActivity {    static final int NUM_ITEMS = 10;    private ViewPager mPager;    private MyAdapter mAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mAdapter = new MyAdapter(getSupportFragmentManager());        mPager = (ViewPager) findViewById(R.id.view_pager);        mPager.setAdapter(mAdapter);        mPager.setPageMargin(10);        mPager.setPageMarginDrawable(android.R.color.background_dark);        Button button = (Button) findViewById(R.id.go_to_first_item);        button.setOnClickListener(new View.OnClickListener() {            public void onClick(View v) {                mPager.setCurrentItem(0);            }        });        button = (Button) findViewById(R.id.go_to_last_item);        button.setOnClickListener(new View.OnClickListener() {            public void onClick(View v) {                mPager.setCurrentItem(NUM_ITEMS - 1);            }        });    }    public static class MyAdapter extends FragmentStatePagerAdapter {        @Override        public float getPageWidth(int position) {            return 0.2f;        }        @Override        public CharSequence getPageTitle(int position) {            return position + "";        }        public MyAdapter(FragmentManager fm) {            super(fm);        }        @Override        public Fragment getItem(int position) {            return MyListFragment.getInstance(position);        }        @Override        public int getCount() {            return NUM_ITEMS;        }    }    public static class MyListFragment extends ListFragment {        private int mNum;        public static MyListFragment getInstance(int position) {            MyListFragment fragment = new MyListFragment();            Bundle args = new Bundle();            args.putInt("position", position);            fragment.setArguments(args);            return fragment;        }        @Override        public void onCreate(Bundle savedInstanceState) {            super.onCreate(savedInstanceState);            mNum = getArguments() == null ? 1 : getArguments().getInt("position");        }        @Override        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {            View view = inflater.inflate(R.layout.fragment_page_item, container, false);            TextView text = (TextView) view.findViewById(R.id.text);            text.setText("Fragment # " + mNum);            return view;        }        @Override        public void onViewCreated(View view, Bundle savedInstanceState) {            super.onViewCreated(view, savedInstanceState);            setListAdapter(                    new ArrayAdapter<String>(getActivity(),                            android.R.layout.simple_list_item_1,                            MyArrays.arrays));        }        @Override        public void onListItemClick(ListView l, View v, int position, long id) {            Log.i("FragmentList", "Item clicked: " + id);        }    }}

这里的fragment继承自ListFragment，在布局文件中ListView的id要设置成android:id/list，然后还有一个id为android:id/empty的textview，当list的adapter的数据为空时，

fragment为显示这个textview。

然后在FragmentStatePagerAdapter中有个getPageSize()的方法，这个方法是制定viewPager中的每个item占整个屏幕的比例，适当的设置这个值可以让viewpager中一次显示多个页面。

下面是效果图：