安卓学习笔记之制作ViewPager欢迎界面

来源：互联网发布：skip java 编辑：程序博客网时间：2024/04/29 21:03

实现步骤

编写布局文件
编写ViewPAger适配器类
初始化ViewPage，设置适配器和滑动监听
初始化ViewPager数据源与页面矩形指示
对ViewPager的页面滑动事件做处理，达到矩形指示跟随手的滑动而滑动
实现跳转到主页

具体代码

布局文件

<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.support.v4.view.ViewPager        android:id="@+id/vp"        android:layout_width="match_parent"        android:layout_height="wrap_content" />    <!-- 页面指示器 -->    <RelativeLayout        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"        android:layout_centerHorizontal="true">        <LinearLayout            android:id="@+id/ll_rect"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:orientation="horizontal"            android:paddingBottom="10dp"/>        <ImageView            android:id="@+id/iv_greenRect"            android:layout_width="wrap_content"            android:layo           android:src="@drawable/rect_green"/>    </RelativeLayout></RelativeLayout>

编写ViewPAger适配器类ViewPagewAdapter类

package com.yu.viewpager02;import android.support.v4.view.PagerAdapter;import android.view.View;import android.view.ViewGroup;import java.util.List;/** * Created by pecu on 2016/07/06. */public class ViewPagewAdapter<T> extends PagerAdapter {    List<T> datas;    public ViewPagewAdapter(List<T> datas) {        this.datas = datas;    }    @Override    public int getCount() {        return datas.size();    }    @Override    public boolean isViewFromObject(View view, Object object) {        return view == object;    }    @Override    public Object instantiateItem(ViewGroup container, int position) {        container.addView((View) datas.get(position));        return datas.get(position);    }    @Override    public void destroyItem(ViewGroup container, int position, Object object) {//        super.destroyItem(container, position, object);        container.removeView((View) datas.get(position));    }}

GuideActivity 类

初始化ViewPage，设置适配器和滑动监听
初始化ViewPager数据源与页面矩形指示
对ViewPager的页面滑动事件做处理，达到矩形指示跟随手的滑动而滑动
实现跳转到主页

package com.yu.viewpager02;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.support.v4.view.ViewPager;import android.view.View;import android.view.ViewGroup;import android.view.ViewTreeObserver;import android.widget.Button;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.RelativeLayout;import java.util.ArrayList;import java.util.List;public class Guide extends Activity implements ViewPager.OnPageChangeListener {    ViewPager vp;    int images[] = new int[]{R.mipmap.guide1, R.mipmap.guide2, R.mipmap.guide3};    List<View> views;    LinearLayout ll_rect; // 灰色矩形容器    ImageView greenRect; // 绿色矩形    int rectMargin; //   矩形间隔    Button btn_enter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();        initrect();        vp = (ViewPager) findViewById(R.id.vp);        vp.setAdapter(new ViewPagewAdapter<View>(views));        vp.addOnPageChangeListener(this);    }    // 初始化用于显示到屏幕的视图    private void initView() {        views = new ArrayList<View>();        for (int i = 0; i < images.length; i++) {            ImageView iv = new ImageView(Guide.this);            iv.setImageResource(images[i]);            views.add(iv);        }        btn_enter = (Button) findViewById(R.id.btn_enter);        btn_enter.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                startActivity(new Intent(Guide.this,MainActivity.class));//跳转到主页                finish();            }        });    }    // 初始化矩形    private void initrect() {        ll_rect = (LinearLayout) findViewById(R.id.ll_rect);        for (int i = 0; i < images.length; i++) {            ImageView iv = new ImageView(Guide.this);            iv.setImageResource(R.drawable.rect_grey);            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, -2);            if (i > 0) params.leftMargin = 10;  // 设置点的间距            iv.setLayoutParams(params);            final int finalI = i;            iv.setOnClickListener(new View.OnClickListener() {  // 设置监听事件                @Override                public void onClick(View v) {                    vp.setCurrentItem(finalI);  // 跳转到指定页                }            });            ll_rect.addView(iv);        }        greenRect = (ImageView) findViewById(R.id.iv_greenRect);        // 设置视图树的监听 当所有view初始化完毕时调用  用于测量两个矩形的中心的距离        greenRect.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {            @Override            public void onGlobalLayout() {                greenRect.getViewTreeObserver().removeOnGlobalLayoutListener(this);                // 两点间距                rectMargin = ll_rect.getChildAt(1).getLeft() - ll_rect.getChildAt(0).getLeft();            }        });    }    /**     * 页面滑动时调用     *     * @param position     * @param positionOffset       参数在[0,1)范围 ， 表示已滑动偏移比例     * @param positionOffsetPixels 滑动偏移量     */    @Override    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {//        System.out.println("positionOffset:"+positionOffset+",positionOffsetPixels:"+positionOffsetPixels);        int leftMargin = (int) (position * rectMargin + positionOffset * rectMargin);        RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) greenRect.getLayoutParams();        params.leftMargin = leftMargin;        greenRect.setLayoutParams(params);    }    // 页面选中时调用    @Override    public void onPageSelected(int position) {        if (position == images.length - 1) btn_enter.setVisibility(View.VISIBLE);        else btn_enter.setVisibility(View.GONE);    }    // 页面状态在变时调用    @Override    public void onPageScrollStateChanged(int state) {    }}

用于绘制矩形的shape

<!-- 当前页矩形 --><?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">    <size android:height="5dp" android:width="20dp"/>    <solid android:color="#0f9"/></shape>----------<?xml version="1.0" encoding="utf-8"?><!-- 非选中 --><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">    <size android:height="4dp" android:width="20dp"/>    <solid android:color="#666"/></shape>

效果图

这里写图片描述

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