Android viewPager 禁止滑动 viewpager自动滑动

转载

月光倾城美 2023-10-08 22:33:32

文章标签 Android ViewPager ide android 启动服务 文章分类 Android 移动开发

Android-ViewPager的自动滑动

在Android-ViewPager循环滑动的基础上添加了自动滑动
添加了一个广播，用于滑动到下一张图片
添加了一个服务，用于向广播发送消息，表示该滑动图片了。。。
效果图

添加的服务代码如下

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;

public class ViewPagerSlideService extends Service{
    private Intent intent;
    public static boolean isRun = true;
    @Override
    public void onCreate() {
        super.onCreate();
        intent = new Intent("com.jz.viewpager.CHANGPAGERRECEIVER");
    }
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        new Thread()
        {
            public void run() 
            {
                while(isRun)
                {//每隔三秒向广播发送消息，滑动到下一张图片
                    try {
                        Thread.sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    sendBroadcast(ViewPagerSlideService.this.intent);
                }
            };

        }.start();
        return super.onStartCommand(intent, flags, startId);
    }

}

改变后的Activity代码如下

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
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.view.ViewGroup.LayoutParams;
import android.widget.ImageView;
import android.widget.LinearLayout;

public class MainActivity extends Activity {
    private ViewPager viewPager;
    private ImageView[] tips;// 小点
    private ImageView[] imageViews;//显示的图片
    private int[] imgIds;//图片的资源id
    private Intent intent;//启动服务的意图
    private ChangePagerReceiver receiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ViewGroup group = (ViewGroup) findViewById(R.id.viewGroup);//获取装小点的线性布局
        viewPager = (ViewPager) findViewById(R.id.viewPager);
        // 图片资源
        imgIds = new int[] { R.drawable.p20, R.drawable.p21, R.drawable.p22};
        tips = new ImageView[imgIds.length];
        for (int i = 0; i < tips.length; i++) {
            ImageView img = new ImageView(this);
            tips[i] = img;
            if (i == 0) {
                tips[i].setImageResource(R.drawable.yuanquan_up2);
            } else {
                tips[i].setImageResource(R.drawable.yuanquan_down2);
            }
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
                    new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
            params.width = 20;//小点宽度
            params.height = 20;//小点高度
            params.leftMargin = 5;//小点的左边margin距离
            params.rightMargin = 5;//小点的右边margin距离
            group.addView(img, params);//将小点添加到线性布局中
        }
        //处理了，当图片小于等于4张的时候报的错
        imageViews = imgIds.length <= 3 ? new ImageView[imgIds.length * 4] : new ImageView[imgIds.length];
        for (int i = 0; i < imageViews.length; i++) {
            imageViews[i] = new ImageView(this);
            imageViews[i].setImageResource(imgIds[i % imgIds.length]);
            //按比例扩大图片的size居中显示，使得图片长(宽)等于或大于View的长(宽) 
            //ImageView.ScaleType参考：
            imageViews[i].setScaleType(ImageView.ScaleType.CENTER_CROP);
        }
        // 设置Adapter
        viewPager.setAdapter(new MyAdapter());
        // 设置监听，主要是设置滑动时点点的图片的改变
        viewPager.addOnPageChangeListener(new OnPageChangeListener() {

            @Override
            public void onPageSelected(int arg0) {
                setImageBack(arg0 % imgIds.length);
            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {

            }

            @Override
            public void onPageScrollStateChanged(int arg0) {

            }
        });
        // 设置ViewPager的默认项, 设置为长度的100倍，这样子开始就能往左滑动
        viewPager.setCurrentItem((imageViews.length) * 100);

添加的部分：调用这个方法，启动服务并且添加广播

startServiceAndBroadcast();//启动服务来发送广播让ViewPager滑动
    }
    /**
     * 启动服务创建广播
     */
    private void startServiceAndBroadcast()
    {
        ViewPagerSlideService.isRun = true;//线程可以运行
        receiver = new ChangePagerReceiver();//实例化广播接收器
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction("com.jz.viewpager.CHANGPAGERRECEIVER");
        registerReceiver(receiver, intentFilter);//添加广播的代码注册
        intent = new Intent(MainActivity.this, ViewPagerSlideService.class);
        startService(intent);//启动服务
    }
    /**
     * 
     * 设置小点的背景
     *
     */
    private void setImageBack(int selectItem) {
        for (int i = 0; i < tips.length; i++) {
            if (i == selectItem) {
                tips[i].setImageResource(R.drawable.yuanquan_up2);
            } else {
                tips[i].setImageResource(R.drawable.yuanquan_down2);
            }
        }
    }
    /**
     * 
     * ViewPager适配器
     *
     */
    public class MyAdapter extends PagerAdapter {

        @Override
        public int getCount() {
            return Integer.MAX_VALUE;
        }

        @Override
        public boolean isViewFromObject(View arg0, Object arg1) {
            return arg0 == arg1;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            container.removeView(imageViews[position % imageViews.length]);
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            container.addView(imageViews[position % imageViews.length], 0);
            return imageViews[position % imageViews.length];
        }
    }

添加的部分：添加的广播接收器，用于切换到下一张图片

/**
     * 
     * 接收广播让ViewPager动态改变
     *
     */
    public class ChangePagerReceiver extends BroadcastReceiver
    {
        @Override
        public void onReceive(Context context, Intent intent) {
            int position = viewPager.getCurrentItem();
            viewPager.setCurrentItem(position + 1, true);
        }
    }

添加的部分：当页面被销毁时

@Override
    protected void onDestroy() {
        super.onDestroy();
        ViewPagerSlideService.isRun = false;
        stopService(intent);
        unregisterReceiver(receiver);
    }
}