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Android-ViewPager自動滑動Android-ViewPager的自動滑動我的感受想說的話

Android-ViewPager的自動滑動

  • 在Android-ViewPager循環滑動的基礎上添加了自動滑動
  • 添加了一個廣播,用于滑動到下一張圖檔
  • 添加了一個服務,用于向廣播發送消息,表示該滑動圖檔了。。。
  • 效果圖
    Android-ViewPager自動滑動Android-ViewPager的自動滑動我的感受想說的話

添加的服務代碼如下

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)
                {//每隔三秒向廣播發送消息,滑動到下一張圖檔
                    try {
                        Thread.sleep();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    sendBroadcast(ViewPagerSlideService.this.intent);
                }
            };

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

}
           

改變後的Activity代碼如下

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;// 小點
    private ImageView[] imageViews;//顯示的圖檔
    private int[] imgIds;//圖檔的資源id
    private Intent intent;//啟動服務的意圖
    private ChangePagerReceiver receiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ViewGroup group = (ViewGroup) findViewById(R.id.viewGroup);//擷取裝小點的線性布局
        viewPager = (ViewPager) findViewById(R.id.viewPager);
        // 圖檔資源
        imgIds = new int[] { R.drawable.p20, R.drawable.p21, R.drawable.p22};
        tips = new ImageView[imgIds.length];
        for (int i = ; i < tips.length; i++) {
            ImageView img = new ImageView(this);
            tips[i] = img;
            if (i == ) {
                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 = ;//小點寬度
            params.height = ;//小點高度
            params.leftMargin = ;//小點的左邊margin距離
            params.rightMargin = ;//小點的右邊margin距離
            group.addView(img, params);//将小點添加到線性布局中
        }
        //處理了,當圖檔小于等于4張的時候報的錯
        imageViews = imgIds.length <=  ? new ImageView[imgIds.length * ] : new ImageView[imgIds.length];
        for (int i = ; i < imageViews.length; i++) {
            imageViews[i] = new ImageView(this);
            imageViews[i].setImageResource(imgIds[i % imgIds.length]);
            //按比例擴大圖檔的size居中顯示,使得圖檔長(寬)等于或大于View的長(寬) 
            //ImageView.ScaleType參考:http://blog.csdn.net/larryl2003/article/details/6919513
            imageViews[i].setScaleType(ImageView.ScaleType.CENTER_CROP);
        }
        // 設定Adapter
        viewPager.setAdapter(new MyAdapter());
        // 設定監聽,主要是設定滑動時點點的圖檔的改變
        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) {

            }
        });
        // 設定ViewPager的預設項, 設定為長度的100倍,這樣子開始就能往左滑動
        viewPager.setCurrentItem((imageViews.length) * );
           

添加的部分:調用這個方法,啟動服務并且添加廣播

startServiceAndBroadcast();//啟動服務來發送廣播讓ViewPager滑動
    }
    /**
     * 啟動服務建立廣播
     */
    private void startServiceAndBroadcast()
    {
        ViewPagerSlideService.isRun = true;//線程可以運作
        receiver = new ChangePagerReceiver();//執行個體化廣播接收器
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction("com.jz.viewpager.CHANGPAGERRECEIVER");
        registerReceiver(receiver, intentFilter);//添加廣播的代碼注冊
        intent = new Intent(MainActivity.this, ViewPagerSlideService.class);
        startService(intent);//啟動服務
    }
    /**
     * 
     * 設定小點的背景
     *
     */
    private void setImageBack(int selectItem) {
        for (int i = ; i < tips.length; i++) {
            if (i == selectItem) {
                tips[i].setImageResource(R.drawable.yuanquan_up2);
            } else {
                tips[i].setImageResource(R.drawable.yuanquan_down2);
            }
        }
    }
    /**
     * 
     * ViewPager擴充卡
     *
     */
    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], );
            return imageViews[position % imageViews.length];
        }
    }

           

添加的部分:添加的廣播接收器,用于切換到下一張圖檔

/**
     * 
     * 接收廣播讓ViewPager動态改變
     *
     */
    public class ChangePagerReceiver extends BroadcastReceiver
    {
        @Override
        public void onReceive(Context context, Intent intent) {
            int position = viewPager.getCurrentItem();
            viewPager.setCurrentItem(position + , true);
        }
    }

           

添加的部分:當頁面被銷毀時

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

我的感受

  • 常常有自動滑動的ViewPager,自己就想着添加一個
  • 也可以直接在Activity中添加一個線程來控制滑動,這樣來的還挺友善快捷的(@ ̄ー ̄@),感覺我好像想多了給弄麻煩了。。。

想說的話

  • 部落格堅持寫,今後學習了新的東西就在這裡記錄一下,以便今後回顧,也希望小小筆記能幫助你們
  • 若内容有什麼地方不對、不清楚,還望吐槽,希望大家能一起成長
  • 來一個:枯燥無味中尋找成功的快感