Android用ViewPager实现欢迎引导页面

jopen 10年前

ViewPager需要android-support-v4.jar这个包的支持,来自google提供的一个附加包。大家搜下即可。

ViewPager主要用来组织一组数据,并且通过左右滑动的方式来展示。

现在的大多数应用都会有一个欢迎引导页面,如图所示,通过左右滑动来告知用户一些功能特性。

 1346732674_4943.jpg

 

 

 

这个引导图效果用ViewPager可以很轻松的实现。

正如前面所说,ViewPager是用来展示一组数据的,所以肯定需要Adapter来绑定数据和view。先写一个Adapter

1、  布局界面比较简单,加入ViewPager组件,以及底部的引导小点:

 <?xml version="1.0" encoding="utf-8"?>    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:orientation="vertical" >             <android.support.v4.view.ViewPager            android:id="@+id/viewpager"            android:layout_width="fill_parent"            android:layout_height="fill_parent" />             <LinearLayout            android:id="@+id/ll"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_alignParentBottom="true"            android:layout_centerHorizontal="true"            android:layout_marginBottom="24.0dip"            android:orientation="horizontal"            >                 <ImageView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center_vertical"                android:clickable="true"                android:padding="15.0dip"                android:src="@drawable/dot"                android:background="@drawable/dot1" />                 <ImageView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center_vertical"                android:clickable="true"                android:padding="15.0dip"                android:src="@drawable/dot"                android:background="@drawable/dot1"                />                 <ImageView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center_vertical"                android:clickable="true"                android:padding="15.0dip"                android:src="@drawable/dot"                  android:background="@drawable/dot1"                />                 <ImageView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center_vertical"                android:clickable="true"                android:padding="15.0dip"                android:src="@drawable/dot"                 android:background="@drawable/dot1"/>        </LinearLayout>         </RelativeLayout>

 

2、其中小点的图片用一个selector来控制颜色(设置itemenabletrue或者false

dot.xml: 

 <?xml version="1.0" encoding="UTF-8"?>    <selector      xmlns:android="http://schemas.android.com/apk/res/android">        <item android:state_enabled="true" android:drawable="@drawable/dark_dot" />        <item android:state_enabled="false" android:drawable="@drawable/white_dot" />    </selector>

 

 

3、  java文件

 import java.util.ArrayList;    import java.util.List;         import android.app.Activity;    import android.os.Bundle;    import android.os.Parcelable;    importandroid.support.v4.view.PagerAdapter;    importandroid.support.v4.view.ViewPager;    importandroid.support.v4.view.ViewPager.OnPageChangeListener;    import android.view.View;    importandroid.view.View.OnClickListener;    import android.widget.ImageView;    import android.widget.LinearLayout;         public class WelcomeActivity extends Activity implementsOnClickListener, OnPageChangeListener{         private ViewPager vp;            private ViewPagerAdapter vpAdapter;            private List<View> views;                       //引导图片资源            private static final int[] pics = { R.drawable.whatsnew_00,                    R.drawable.whatsnew_01, R.drawable.whatsnew_02,                    R.drawable.whatsnew_03 };                       //底部小店图片            private ImageView[] dots ;                       //记录当前选中位置            private int currentIndex;                                  @Override            public void onCreate(Bundle savedInstanceState) {                super.onCreate(savedInstanceState);                setContentView(R.layout.main);                               views = new ArrayList<View>();                              LinearLayout.LayoutParams mParams =newLinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,                        LinearLayout.LayoutParams.WRAP_CONTENT);                               //初始化引导图片列表                for(int i=0; i<pics.length; i++) {                    ImageView iv = new ImageView(this);                    iv.setLayoutParams(mParams);                    iv.setImageResource(pics[i]);                    views.add(iv);                }                vp = (ViewPager) findViewById(R.id.viewpager);                //初始化Adapter                vpAdapter = new ViewPagerAdapter(views);                vp.setAdapter(vpAdapter);                //绑定回调                vp.setOnPageChangeListener(this);                               //初始化底部小点                initDots();                           }                       private void initDots() {                LinearLayout ll = (LinearLayout) findViewById(R.id.ll);                                   dots = new ImageView[pics.length];                     //循环取得小点图片                for (int i = 0; i < pics.length; i++) {                //得到一个LinearLayout下面的每一个子元素                    dots[i] = (ImageView) ll.getChildAt(i);                    dots[i].setEnabled(true);//都设为灰色                    dots[i].setOnClickListener(this);                    dots[i].setTag(i);//设置位置tag,方便取出与当前位置对应                }                     currentIndex = 0;                dots[currentIndex].setEnabled(false);//设置为白色,即选中状态            }                                  private void setCurView(int position)            {                if (position < 0 || position >= pics.length) {                    return;                }                     vp.setCurrentItem(position);            }                            private void setCurDot(int positon)            {                if (positon < 0 || positon > pics.length - 1 || currentIndex == positon) {                    return;                }                     dots[positon].setEnabled(false);                dots[currentIndex].setEnabled(true);                     currentIndex = positon;            }                 //当滑动状态改变时调用            @Override            public void onPageScrollStateChanged(int arg0) {                // TODO Auto-generated method stub                           }                 //当当前页面被滑动时调用            @Override            public void onPageScrolled(int arg0, float arg1, int arg2) {                // TODO Auto-generated method stub                           }                 //当新的页面被选中时调用            @Override            public void onPageSelected(int arg0) {                //设置底部小点选中状态                setCurDot(arg0);            }                 @Override            public void onClick(View v) {                int position = (Integer)v.getTag();                setCurView(position);                setCurDot(position);            }        public class ViewPagerAdapter extends PagerAdapter{                       //界面列表            private List<View> views;                       public ViewPagerAdapter (List<View> views){                this.views = views;            }                 //销毁arg1位置的界面            @Override            public void destroyItem(View arg0, int arg1, Object arg2) {                ((ViewPager) arg0).removeView(views.get(arg1));                   }                 @Override            public void finishUpdate(View arg0) {                // TODO Auto-generated method stub                           }                 //获得当前界面数            @Override            public int getCount() {                if (views != null)                {                    return views.size();                }                               return 0;            }                            //初始化arg1位置的界面            @Override            public Object instantiateItem(View arg0, int arg1) {                               ((ViewPager) arg0).addView(views.get(arg1), 0);                               return views.get(arg1);            }                 //判断是否由对象生成界面            @Override            public boolean isViewFromObject(View arg0, Object arg1) {                return (arg0 == arg1);            }                 @Override            public void restoreState(Parcelable arg0, ClassLoader arg1) {                // TODO Auto-generated method stub                           }                 @Override            public Parcelable saveState() {                // TODO Auto-generated method stub                return null;            }                 @Override            public void startUpdate(View arg0) {                // TODO Auto-generated method stub                           }             }