Android引导页的实现

实现原理：使用ViewPager控件（com.android.support:support-v4:22.1.1），把引导页的layout文件放进ViewPager控件就可以了。

ViewPager控件本质上也是个列表控件，横向滚动，一个页面一个页面的滚动，底下并没有滚动条，所以非常适合做引导页，和页签的tap控件来做横向滚动的页面也非常常用。

首先引用 com.android.support:support-v4:22.1.1

引导页面的layout

<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="demo.viewpagerdemo.GuideActivity">

    <android.support.v4.view.ViewPager
        android:id="@+id/guide_activity_viewpager"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
    </android.support.v4.view.ViewPager>

</RelativeLayout>

package demo.viewpagerdemo;

import android.app.Activity;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;

import java.util.ArrayList;
import java.util.List;

public class GuideActivity extends Activity {

    private View mPage1, mPage2, mPage3;

    private List<View> mViews = new ArrayList<View>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_guide);

        ViewPager vp=(ViewPager)findViewById(R.id.guide_activity_viewpager);

        mPage1 = LayoutInflater.from(this).inflate(
                R.layout.guide_page1, null);
        mPage2 = LayoutInflater.from(this).inflate(
                R.layout.guide_page2, null);
        mPage3 = LayoutInflater.from(this).inflate(
                R.layout.guide_page3, null);
        mViews.add(mPage1);
        mViews.add(mPage2);
        mViews.add(mPage3);
        vp.setAdapter(new BasePagerAdapter(this, mViews));

    }

}

注意ViewPager需要使用PagerAdapter适配器，所以需要继承PagerAdapter类来实现一个适配器

public class BasePagerAdapter extends PagerAdapter {

    private Context mContext;
    private List<? extends View> mViews;

    public BasePagerAdapter(Context mContext, List<? extends View> mViews) {
        this.mContext = mContext;
        this.mViews = mViews;
    }

    @Override
    public int getCount() {
        return mViews.size();
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        container.addView(mViews.get(position));
        return mViews.get(position);
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        container.removeView(mViews.get(position));
    }
}