AndroidViewPager实现每隔两秒自动切换图片功能

Qoqa ·

更新时间:2024-09-20

· 881 次阅读

布局代码：


<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" >
    <FrameLayout
        android:layout_width="fill_parent"
        android:layout_height="200dip"
        >
        <android.support.v4.view.ViewPager
            android:id="@+id/vp"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            />
        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="35dip"
            android:orientation="vertical"
            android:layout_gravity="bottom"
            android:gravity="center"
            android:background="#33000000"
            >
            <TextView
                android:id="@+id/title"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="图片标题"
                android:textColor="@android:color/white"
                />
            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:layout_marginTop="3dip"
                >
                <View
                    android:id="@+id/dot_0"
                    android:layout_width="5dip"
                    android:layout_height="5dip"
                    android:layout_marginLeft="2dip"
                    android:layout_marginRight="2dip"
                    android:background="@drawable/dot_focused"
                    />
                <View
                    android:id="@+id/dot_1"
                    android:layout_width="5dip"
                    android:layout_height="5dip"
                    android:layout_marginLeft="2dip"
                    android:layout_marginRight="2dip"
                    android:background="@drawable/dot_normal"
                    />
                <View
                    android:id="@+id/dot_2"
                    android:layout_width="5dip"
                    android:layout_height="5dip"
                    android:layout_marginLeft="2dip"
                    android:layout_marginRight="2dip"
                    android:background="@drawable/dot_normal"
                    />
                <View
                    android:id="@+id/dot_3"
                    android:layout_width="5dip"
                    android:layout_height="5dip"
                    android:layout_marginLeft="2dip"
                    android:layout_marginRight="2dip"
                    android:background="@drawable/dot_normal"
                    />
                <View
                    android:id="@+id/dot_4"
                    android:layout_width="5dip"
                    android:layout_height="5dip"
                    android:layout_marginLeft="2dip"
                    android:layout_marginRight="2dip"
                    android:background="@drawable/dot_normal"
                    />
            </LinearLayout>
        </LinearLayout>
    </FrameLayout>
</RelativeLayout>

正常的shape图形dot_normal.xml：


<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval"
    >
    <corners android:radius="5dip" />
    <solid android:color="#55000000" />
</shape>

获取焦点的shape图形 dot_focused.xml


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

具体实现代码：


import java.util.ArrayList;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
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.TextView;
public class MainActivity extends Activity {
    private int imageIds[];
    private String[] titles;
    private ArrayList<ImageView> images;
    private ArrayList<View> dots;
    private TextView title;
    private ViewPager mViewPager;
    private ViewPagerAdapter adapter;
    private int oldPosition = 0;//记录上一次点的位置
    private int currentItem; //当前页面
    private ScheduledExecutorService scheduledExecutorService;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //图片ID
        imageIds = new int[]{
            R.drawable.a,
            R.drawable.b,
            R.drawable.c,
            R.drawable.d,
            R.drawable.e
        };
        //图片标题
        titles = new String[]{
            "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",
            "热血的反杀"
        };
        //显示的图片
        images = new ArrayList<ImageView>();
        for(int i =0; i < imageIds.length; i++){
            ImageView imageView = new ImageView(this);
            imageView.setBackgroundResource(imageIds[i]);
            images.add(imageView);
        }
        //显示的点
        dots = new ArrayList<View>();
        dots.add(findViewById(R.id.dot_0));
        dots.add(findViewById(R.id.dot_1));
        dots.add(findViewById(R.id.dot_2));
        dots.add(findViewById(R.id.dot_3));
        dots.add(findViewById(R.id.dot_4));
        title = (TextView) findViewById(R.id.title);
        title.setText(titles[0]);
        mViewPager = (ViewPager) findViewById(R.id.vp);
        adapter = new ViewPagerAdapter();
        mViewPager.setAdapter(adapter);
        mViewPager.setOnPageChangeListener(new OnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {
                // TODO Auto-generated method stub
                title.setText(titles[position]);
                dots.get(oldPosition).setBackgroundResource(R.drawable.dot_normal);
                dots.get(position).setBackgroundResource(R.drawable.dot_focused);
                oldPosition = position;
                currentItem = position;
            }
            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
                // TODO Auto-generated method stub
            }
            @Override
            public void onPageScrollStateChanged(int arg0) {
                // TODO Auto-generated method stub
            }
        });
    }
    private class ViewPagerAdapter extends PagerAdapter {
        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return images.size();
        }
        //是否是同一张图片
        @Override
        public boolean isViewFromObject(View arg0, Object arg1) {
            // TODO Auto-generated method stub
            return arg0 == arg1;
        }
        @Override
        public void destroyItem(ViewGroup view, int position, Object object) {
            // TODO Auto-generated method stub
//            super.destroyItem(container, position, object);
//            view.removeViewAt(position);
            view.removeView(images.get(position));
        }
        @Override
        public Object instantiateItem(ViewGroup view, int position) {
            // TODO Auto-generated method stub
            view.addView(images.get(position));
            return images.get(position);
        }
    }
    @Override
    protected void onStart() {
        // TODO Auto-generated method stub
        super.onStart();
        scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
        //每隔2秒钟切换一张图片
        scheduledExecutorService.scheduleWithFixedDelay(new ViewPagerTask(), 2, 2, TimeUnit.SECONDS);
    }
    //切换图片
    private class ViewPagerTask implements Runnable {
        @Override
        public void run() {
            // TODO Auto-generated method stub
            currentItem = (currentItem +1) % imageIds.length;
            //更新界面
//            handler.sendEmptyMessage(0);
            handler.obtainMessage().sendToTarget();
        }
    }
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            // TODO Auto-generated method stub
            //设置当前页面
            mViewPager.setCurrentItem(currentItem);
        }
    };
    @Override
    protected void onStop() {
        // TODO Auto-generated method stub
        super.onStop();
    }
}

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