Android最简单的轮播图实现

淡淡的烟草味﹌ 2022-07-14 03:43 164阅读 0赞

最简单的轮播图

参考[http://www.cnblogs.com/xurui1995/p/5759371.html][http_www.cnblogs.com_xurui1995_p_5759371.html]博文

xml布局

<?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="wrap_content"
        tools:context="com.example.playpicture.MainActivity">
    
        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="180dp">
    
            <android.support.v4.view.ViewPager
                android:id="@+id/vp"
                android:layout_width="match_parent"
                android:layout_height="match_parent">
    
            </android.support.v4.view.ViewPager>
    
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="30dp"
                android:layout_alignParentBottom="true"
                android:background="#66000000"
                android:orientation="horizontal">
    
                <LinearLayout
                    android:id="@+id/point_container"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center"
                    android:gravity="center"
                    android:orientation="horizontal">
    
                </LinearLayout>
            </LinearLayout>
        </RelativeLayout>
    </RelativeLayout>

在Drawable下新建下面3个Drawable resource file

bg\_shape

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android"
        android:shape="oval">
        <corners android:radius="5dp"/>
        <solid android:color="#FFFFFF"/>
    </shape>

bg\_shape2

selector

<?xml version="1.0" encoding="utf-8"?>
    <selector xmlns:android="http://schemas.android.com/apk/res/android">
        <item android:drawable="@drawable/bg_shape" android:state_enabled="true" />
        <item android:drawable="@drawable/bg_shape2" android:state_enabled="false" />
    </selector>

下面是完整代码：

package com.example.playpicture;
    
    import android.os.Bundle;
    import android.support.v4.view.PagerAdapter;
    import android.support.v4.view.ViewPager;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ImageView;
    import android.widget.LinearLayout;
    
    import java.util.ArrayList;
    
    /**
     * 在Activity中使用页面改变监听实现可以手动滑动的轮播图
     */
    public class MainActivity extends AppCompatActivity implements ViewPager.OnPageChangeListener{
        private ViewPager vp;
        private  int[] imas;
        private LinearLayout ll;
        private ArrayList<ImageView> imaList;
        private Boolean flag;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            //初始化布局
            initViews();
            //数据
            initData();
    
            //适配器
            initAdapter();
            flag=true;
            //实现自动轮播
            new Thread(new Runnable() {
                @Override
                public void run() {
    
                    while (flag) {
                        try {
                            Thread.sleep(2000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        //这里加上MainActivity.this获取当前context环境
                        MainActivity.this.runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                vp.setCurrentItem(vp.getCurrentItem() + 1);
                            }
                        });
                    }
                }
            }).start();
        }
    
        private void initAdapter() {
            ll.getChildAt(0).setEnabled(true);
            vp.setAdapter(new MyAdapter());
            vp.setCurrentItem(Integer.MAX_VALUE/2+2);//这里以一个%5为0的数开始，这样打开默认会在第0个item显示
        }
    
        @Override
        protected void onDestroy() {
            super.onDestroy();
            flag=false;
        }
    
        private void initData() {
        }
    
        private void initViews() {
            vp = (ViewPager) findViewById(R.id.vp);
            vp.setOnPageChangeListener(this);
            ll= (LinearLayout) findViewById(R.id.point_container);
            //图片数组，将要实现轮播的图片放这数组里
            imas = new int[]{R.drawable.pic1, R.drawable.pic2, R.drawable.pic3, R.drawable.pic4, R.drawable.pic5,};
            ImageView iv;
            imaList = new ArrayList<ImageView>();
            View pointview;
            for (int i = 0; i < imas.length; i++) {
                iv = new ImageView(this);
                iv.setImageResource(imas[i]);
                imaList.add(iv);
    
                //加小白点
                pointview =new View(this);
                pointview.setEnabled(false);
                pointview.setBackgroundResource(R.drawable.selector);
                LinearLayout.LayoutParams params =new LinearLayout.LayoutParams(15,15);
                //params.gravity= Gravity.CENTER;
                if(i!=0)
                    params.leftMargin=10;
                ll.addView(pointview,
                        params );
            }
    
        }
    
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
    
        }
    
        @Override
        public void onPageSelected(int position) {
            for(int i=0;i<ll.getChildCount();i++){
                ll.getChildAt(i).setEnabled(false);
            }
            ll.getChildAt(position%5).setEnabled(true);//设置小白点
        }
    
        @Override
        public void onPageScrollStateChanged(int state) {
    
        }
    
    
        class MyAdapter extends PagerAdapter {
            @Override
            public Object instantiateItem(ViewGroup container, int position) {
                int newposition =position%5;//得到新位置
                ImageView imageView=imaList.get(newposition);
                container.addView(imageView);
                return imageView;//把View对象返回给框架，必须重写
            }
    
    
    
    
            @Override
            public void destroyItem(ViewGroup container, int position, Object object) {
                container.removeView((View) object);
    
            }
    
            @Override
            public int getCount() {
                return Integer.MAX_VALUE;
            }
    
            @Override //判断复用
            public boolean isViewFromObject(View view, Object object) {
                return view==object;
            }
    
    
        }
    }

这就是最简单的轮播图实现（经测试）

[http_www.cnblogs.com_xurui1995_p_5759371.html]: http://www.cnblogs.com/xurui1995/p/5759371.html