Android大图轮播-学习笔记

来源：互联网发布：姓氏笔画排列软件编辑：程序博客网时间：2024/06/06 23:17

Android大图轮播-学习笔记

图片轮播组合控件如：
这里写图片描述
图片可以轮播，现在我们可以一点一点开发

ViewPager框架

首先明确大框架是ViewPager然后整个布局是RelativeLayout，其中ViewPager布满整个布局，之下是一个线性布局线性布局中有文字和小点两种View，CiewPager是V4包下的，布局文件如下：

<?xml version="1.0" encoding="utf-8"?><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="160dp"    tools:context="com.hty.ad.MainActivity">    <android.support.v4.view.ViewPager        android:id="@+id/view_pager"        android:layout_width="match_parent"        android:layout_height="match_parent"/>    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="vertical"        android:layout_alignParentBottom="true"        android:background="#25000000">        <TextView            android:paddingBottom="5dp"            android:id="@+id/text_view"            android:text="调试完毕"            android:gravity="center"            android:textSize="20sp"            android:textColor="#ffffff"            android:layout_width="match_parent"            android:layout_height="wrap_content"/>        <LinearLayout            android:id="@+id/dot_layout"            android:layout_width="match_parent"            android:orientation="horizontal"            android:layout_height="20dp"            android:gravity="center">        </LinearLayout>    </LinearLayout></RelativeLayout>

定义Adapter填充ViewPager

定义一个MyAdapter继承PagerAdapter然后实现getcount（）方法和isviewFromObject（）方法

代码如下：

   class MyAdapter extends PagerAdapter {        @Override        public int getCount() {            return Integer.MAX_VALUE;        }/**         * true: 表示不去创建，使用缓存  false:去重新创建         * view： 当前滑动的view         * object：将要进入的新创建的view，由instantiateItem方法创建         */        @Override        public boolean isViewFromObject(View view, Object object) {            return view == object;        }

封装javaBean填充MyAdapter

package com.hty.ad;/** * 作者：司马啸尘 * 创建日期：2016/4/12 * 描述： */public class Ad {    private int icon;    private String into;    public Ad(int icon, String into) {        this.icon = icon;        this.into = into;    }    public int getIcon() {        return icon;    }    public void setIcon(int icon) {        this.icon = icon;    }    public String getInto() {        return into;    }    public void setInto(String into) {        this.into = into;    }}

对bean赋值并且在MyAdapter中初始化视图

private void initData() {        mAds = new ArrayList<Ad>();        mAds.add(new Ad(R.drawable.c, "哈哈哈哈h"));        mAds.add(new Ad(R.drawable.c, "ddddddh"));        mAds.add(new Ad(R.drawable.c, "vvvvvv哈h"));        mViewPager.setAdapter(new MyAdapter());        Log.d("setAdapter", "------------");        }

在MyAdapter中重写instantianteItem方法

 public Object instantiateItem(ViewGroup container, int position) {            View view = View.inflate(MainActivity.this, R.layout.dapter_ad, null);            ImageView imageView = (ImageView) view.findViewById(R.id.iv_body);            imageView.setImageResource(mAds.get(position % mAds.size()).getIcon());            container.addView(view);            return view;        }

现在就可以实现滑动但是在边界不能滑动，而且小点和文字不同步

同步小点和文字

对mViewAdapter设置监听，api变化成addOnPagerChangeLiatener，初始化监听器

private void initListener() {        mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {            @Override            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {            }            @Override            public void onPageSelected(int position) {                update();            }            @Override            public void onPageScrollStateChanged(int state) {            }        });    }

设置事件同步

private void update() {        int currentPosition = mViewPager.getCurrentItem();        mTextView.setText(mAds.get(currentPosition % mAds.size()).getInto());        for (int i = 0; i < mLinearLayout.getChildCount(); i++) {            mLinearLayout.getChildAt(i).setEnabled(i == currentPosition % mAds.size());        }    }

解决到边界的问题

就是把所有位置变成position % mAds.size()而不是position
然后再添加周期改变：

 android.os.Handler mHandler = new android.os.Handler() {        @Override        public void handleMessage(Message msg) {            mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1);            mHandler.sendEmptyMessageDelayed(0, 1000);        }    };

完整java代码

package com.hty.ad;import android.os.Bundle;import android.os.Message;import android.support.v4.view.PagerAdapter;import android.support.v4.view.ViewPager;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.TextView;import java.util.ArrayList;public class MainActivity extends AppCompatActivity {    private ViewPager mViewPager;    private ArrayList<Ad> mAds;    private TextView mTextView;    private LinearLayout mLinearLayout;    android.os.Handler mHandler = new android.os.Handler() {        @Override        public void handleMessage(Message msg) {            mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1);            mHandler.sendEmptyMessageDelayed(0, 1000);        }    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        initView();        initData();        initListener();    }    private void initListener() {        mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {            @Override            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {            }            @Override            public void onPageSelected(int position) {                update();            }            @Override            public void onPageScrollStateChanged(int state) {            }        });    }    private void update() {        int currentPosition = mViewPager.getCurrentItem();        mTextView.setText(mAds.get(currentPosition % mAds.size()).getInto());        for (int i = 0; i < mLinearLayout.getChildCount(); i++) {            mLinearLayout.getChildAt(i).setEnabled(i == currentPosition % mAds.size());        }    }    private void initView() {        setContentView(R.layout.activity_main);        mViewPager = (ViewPager) findViewById(R.id.view_pager);        mTextView = (TextView) findViewById(R.id.text_view);        mLinearLayout = (LinearLayout) findViewById(R.id.dot_layout);    }    private void initData() {        mAds = new ArrayList<Ad>();        mAds.add(new Ad(R.drawable.c, "哈哈哈哈h"));        mAds.add(new Ad(R.drawable.c, "ddddddh"));        mAds.add(new Ad(R.drawable.c, "vvvvvv哈h"));        mViewPager.setAdapter(new MyAdapter());        Log.d("setAdapter", "------------");        int center = Integer.MAX_VALUE / 2;        mViewPager.setCurrentItem(center);        initDot();        mHandler.sendEmptyMessageDelayed(0, 1000);        update();    }    private void initDot() {        for (int i = 0; i < mAds.size(); i++) {            View view = new View(MainActivity.this);            view.setBackgroundResource(R.drawable.selector);            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(20, 20);            layoutParams.setMargins(10, 0, 0, 0);            view.setLayoutParams(layoutParams);            mLinearLayout.addView(view);        }    }    class MyAdapter extends PagerAdapter {        @Override        public int getCount() {            return Integer.MAX_VALUE;        }        @Override        public boolean isViewFromObject(View view, Object object) {            return view == object;        }        @Override        public void destroyItem(ViewGroup container, int position, Object object) {//            super.destroyItem(container, position, object);            container.removeView((View) object);        }        @Override        public Object instantiateItem(ViewGroup container, int position) {            View view = View.inflate(MainActivity.this, R.layout.dapter_ad, null);            ImageView imageView = (ImageView) view.findViewById(R.id.iv_body);            imageView.setImageResource(mAds.get(position % mAds.size()).getIcon());            container.addView(view);            return view;        }    }}

PS：有几天没有更新博客了，四月好美加油

1 0