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Android广告条滚动效果
一、效果图
二、主要技术点
1.ViewPager的使用
2.背景选择器
3.自动播放
三、示例代码
1.布局文件：activity_main.xml
<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="200dp" > <android.support.v4.view.ViewPager android:id="@+id/vp_show" android:layout_width="match_parent" android:layout_height="200dp" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:background="#33000000" android:gravity="center" android:orientation="vertical" > <TextView android:id="@+id/tv_description" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="标题" android:textSize="16sp" android:textColor="#FFFFFFFF"/> <LinearLayout android:id="@+id/ll_viewgroup" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" > </LinearLayout> </LinearLayout></RelativeLayout>
2.图片下面的指示点背景imageview_point_normal.xml，imageview_point_focused.xml，imageview_selector.xml
（1）imageview_point_normal.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" > <size android:height="5dp" android:width="5dp" /> <solid android:color="#55000000" /></shape>
（2）imageview_point_focused.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" > <size android:height="5dp" android:width="5dp" /> <solid android:color="#AAFFFFFF" /></shape>
（3）imageview_selector.xml
<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:drawable="@drawable/imageview_point_focused" android:state_enabled="true"></item> <item android:drawable="@drawable/imageview_point_normal" android:state_enabled="false"></item></selector>
3.主页面MainActivity.java
package com.gnnuit.banner;import java.util.ArrayList;import java.util.List;import android.os.Bundle;import android.os.Handler;import android.app.Activity;import android.content.Context;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.support.v4.view.ViewPager.OnPageChangeListener;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.LinearLayout.LayoutParams;import android.widget.TextView;public class MainActivity extends Activity { private ViewPager vp_show; private TextView tv_description; private LinearLayout ll_viewgroup; private final int[] ids = { R.drawable.a, R.drawable.b, R.drawable.c, R.drawable.d, R.drawable.e }; private final String[] descriptions = { "巩俐不低俗，我就不能低俗", "扑树又回来啦！再唱经典老歌引万人大合唱", "揭秘北京电影如何升级", "乐视网TV版大派送", "热血屌丝的反杀" }; private List<ImageView> imageViewList = new ArrayList<ImageView>(); private int lastposition = 0;// 记录上一个页面的位置 private boolean isRunning = false;// 记录ViewPager正在播放 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); vp_show = (ViewPager) findViewById(R.id.vp_show); tv_description = (TextView) findViewById(R.id.tv_description); ll_viewgroup = (LinearLayout) findViewById(R.id.ll_viewgroup); // 初始化资源 for (int i = 0; i < ids.length; i++) { // 初始化图片资源 ImageView iv = new ImageView(this); iv.setBackgroundResource(ids[i]); imageViewList.add(iv); // 初始化指示点 ImageView iv_point = new ImageView(this); LinearLayout.LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT); params.rightMargin = px2dip(this, 10); params.topMargin = px2dip(this, 5); iv_point.setLayoutParams(params); iv_point.setBackgroundResource(R.drawable.imageview_selector); iv_point.setEnabled(false); ll_viewgroup.addView(iv_point); } tv_description.setText(descriptions[0]); ll_viewgroup.getChildAt(0).setEnabled(true); // 设置ViewPager的Adapter vp_show.setAdapter(new MyAdapter()); // 设置ViewPager的OnPageChangeListener事件 vp_show.setOnPageChangeListener(new OnPageChangeListener() { /** * 显示一个新的页面时执行 */ @Override public void onPageSelected(int position) { tv_description.setText(descriptions[position]); ll_viewgroup.getChildAt(position).setEnabled(true); ll_viewgroup.getChildAt(lastposition).setEnabled(false); lastposition = position; } /** * 页面正在滑动时调用 */ @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } /** * 页面状态发生变化时调用 */ @Override public void onPageScrollStateChanged(int state) { } }); isRunning = true; myHandler.sendEmptyMessageDelayed(0, 2000); } private Handler myHandler = new Handler() { public void handleMessage(android.os.Message msg) { vp_show.setCurrentItem((vp_show.getCurrentItem() + 1)%imageViewList.size()); if (isRunning) { myHandler.sendEmptyMessageDelayed(0, 2000); } }; }; private class MyAdapter extends PagerAdapter { /** * 获得页面的总数 */ @Override public int getCount() { return imageViewList.size(); } /** * 判断View和Object的对应关系 */ @Override public boolean isViewFromObject(View view, Object object) { return view == object; } /** * 获得相应位置上的View * * @param container * View的容器，其实就是ViewPager自身 * @param position * 相应的位置 */ @Override public Object instantiateItem(ViewGroup container, int position) { container.addView(imageViewList.get(position)); return imageViewList.get(position); } /** * 销毁对应位置上的Object */ @Override public void destroyItem(ViewGroup container, int position, Object object) { container.removeView((View) object); object = null; } } /** * 根据手机的分辨率从 px(像素) 的单位 转成为 dp */ public static int px2dip(Context context, float pxValue) { final float scale = context.getResources().getDisplayMetrics().density; return (int) (pxValue / scale + 0.5f); }}
Android广告条滚动效果
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