ViewPager的简单使用

1、布局文件

a、主布局文件

<?xml version="1.0" encoding="utf-8"?>
<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"
    tools:context="lpc.com.animation2demo.MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="48dp">

        <TextView
            android:id="@+id/tv1"
            android:text="苹果"
            android:gravity="center"
            android:layout_weight="1"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />


        <TextView
            android:id="@+id/tv2"
            android:text="香蕉"
            android:gravity="center"
            android:layout_weight="1"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />


        <TextView
            android:text="梨"
            android:id="@+id/tv3"
            android:gravity="center"
            android:layout_weight="1"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    </LinearLayout>


    <ImageView
        android:id="@+id/iv"
        android:src="@mipmap/line"
        android:scaleType="matrix"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <android.support.v4.view.ViewPager
        android:id="@+id/viewPager1"
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:flipInterval="30"
        android:layout_gravity="center"
        android:persistentDrawingCache="animation"
        android:layout_height="0dp">

    </android.support.v4.view.ViewPager>

</LinearLayout>

b、子布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:background="@drawable/a1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

另外两子布局类似，只是图片和id不一样

2、主Java文件

package lpc.com.animation2demo;

import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.util.DisplayMetrics;
import android.view.LayoutInflater;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity implements View.OnClickListener,ViewPager.OnPageChangeListener{

    private TextView tv1; //文本对象1
    private TextView tv2; //文本对象2
    private TextView tv3; //文本对象3
    private ImageView iv; //图片对象（用于移动条）
    private ViewPager vp; //Viewpager对象

    private ArrayList<View> viewArrayList; //创建一个View储存数组
    private int offset = 0; //移动条图片的偏移量
    private int currentIndex = 0; //当前页面
    private int bmpWidth ; //图片宽度
    private int one = 0; //移动条滑动一页的距离
    private int two = 0; //滑动条移动两页的距离


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView();
    }

    private void initView() {

       tv1 = (TextView) findViewById(R.id.tv1);
       tv2 = (TextView) findViewById(R.id.tv2);
       tv3 = (TextView) findViewById(R.id.tv3);
        iv = (ImageView) findViewById(R.id.iv);
        vp = (ViewPager) findViewById(R.id.viewPager1);

        //下划线动画的相关设置：
        bmpWidth = BitmapFactory.decodeResource(getResources(), R.mipmap.line).getWidth();// 获取图片宽度
        DisplayMetrics dm = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(dm);
        int screenW = dm.widthPixels;// 获取分辨率宽度
        offset = (screenW / 3 - bmpWidth) / 2;// 计算偏移量
        Matrix matrix = new Matrix();
        matrix.postTranslate(offset, 0);
        iv.setImageMatrix(matrix);// 设置动画初始位置
        //移动的距离
        one = offset * 2 + bmpWidth;// 移动一页的偏移量,比如1->2,或者2->3
        two = one * 2;// 移动两页的偏移量,比如1直接跳3


        //往ViewPager填充View，同时设置点击事件与页面切换事件

        viewArrayList = new ArrayList<View>();
        LayoutInflater inflater = getLayoutInflater();
        viewArrayList.add(inflater.inflate(R.layout.view1,null,false));
        viewArrayList.add(inflater.inflate(R.layout.view2,null,false));
        viewArrayList.add(inflater.inflate(R.layout.view3,null,false));

        vp.setAdapter(new MyAdapter(viewArrayList));
        vp.setCurrentItem(0); //设置ViewPager当前页，从0开始算

        tv1.setOnClickListener(this);
        tv2.setOnClickListener(this);
        tv3.setOnClickListener(this);

        vp.addOnPageChangeListener(this);

    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.tv1:
                vp.setCurrentItem(0);
                break;
            case R.id.tv2:
                vp.setCurrentItem(1);
                break;
            case R.id.tv3:
                vp.setCurrentItem(2);
                break;
        }
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

    }

    @Override
    public void onPageSelected(int position) {

        Animation animation = null;
        switch (position){
            case 0:
                if (currentIndex == 1){
                    animation = new TranslateAnimation(one,0,0,0);
                }else if (currentIndex == 2){
                    animation = new TranslateAnimation(two,0,0,0);
                }
                break;
            case 1:
                if (currentIndex == 0){
                    animation = new TranslateAnimation(offset,one,0,0);
                }else if (currentIndex == 2){
                    animation = new TranslateAnimation(two,one,0,0);
                }
                break;
            case 2:
                if (currentIndex == 0){
                    animation = new TranslateAnimation(offset,two,0,0);
                }else if (currentIndex == 1){
                    animation = new TranslateAnimation(one,two,0,0);
                }
                break;
        }
        currentIndex = position;
        animation.setFillAfter(true);// true表示图片停在动画结束位置
        animation.setDuration(300); //设置动画时间为300毫秒
        iv.startAnimation(animation);//开始动画

    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }
}

3、适配器文件

package lpc.com.animation2demo;

import android.support.v4.view.PagerAdapter;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;

/**
 * Created by Administrator on 2016/3/16.
 * 适配器
 */
public class MyAdapter extends PagerAdapter {

    //创建一个对象数组 存储View
    private ArrayList<View> viewArrayList;

    //空构造函数
    public MyAdapter() {
    }

    //初始化对象数组
    public MyAdapter(ArrayList<View> viewArrayList) {
        this.viewArrayList = viewArrayList;
    }

    //获取对象数组的大小
    @Override
    public int getCount() {
        return viewArrayList.size();
    }
    //将视图转化成对象
    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

    //获取选定 对象数组并将其添加到viewpager中
    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        container.addView(viewArrayList.get(position));
        return viewArrayList.get(position);
    }

    //移除选定的对象数组对象
    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView(viewArrayList.get(position));
    }
}

4、manifest文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="lpc.com.animation2demo">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

5、实现效果

来自为知笔记(Wiz)