利用MVC编写广告条轮播效果

我理解的安卓中MVC思想是利用Holder进行编程,展示布局,提供视图,将视图和数据进行绑定起来,在很多App中我们能见到广告条,广告条这里我们可以使用FramLayout进行填充，然后利用MVC的思想将提供的布局添加到FrameLayout中即可; 广告条的实现也可以利用Banner等开源框架等,这里就不列举了,感兴趣的朋友可以去搜下

当然由于我这里的项目的图片是设计师那边提供好的,并不是从网上获取的,所以我这里就直接写了ViewPager来进行填充了

<!--轮播图-->
  <RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="328px"> 

    <android.support.v4.view.ViewPager
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/fragment_work_pic_viewpager"/> 

    <!-- 指针容器 --> 

    <RelativeLayout
      android:background="@android:color/transparent"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:padding="5dp"
      android:layout_alignBottom="@id/fragment_work_pic_viewpager"> 

    <!--<TextView
      android:textSize="12sp"
      android:layout_gravity="left"
      android:layout_marginLeft="5dp"
      android:id="@+id/tv_desc"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:textColor="@android:color/white"
      android:text="图片的描述"/>--> 

    <LinearLayout
      android:layout_centerHorizontal="true"
      android:layout_centerVertical="true"
      android:id="@+id/ll_dots"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:orientation="horizontal"> 

      </LinearLayout>
    </RelativeLayout>

逻辑:

package com.hanzheng.znxl.fragment; 

import android.support.v4.view.ViewPager;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout; 

import com.hanzheng.znxl.R;
import com.hanzheng.znxl.adapter.OnPagerChangeListenerImp;
import com.hanzheng.znxl.adapter.WorkFragmentBannerAdapter;
import com.hanzheng.znxl.base.BaseFragment;
import com.hanzheng.znxl.base.MyApplication;
import com.hanzheng.znxl.utils.ToastUtil; 

import butterknife.Bind;
import butterknife.ButterKnife;
import butterknife.OnClick; 

/**
 * Created by zmybi on 29/12/2016.
 */
public class WorkFragment extends BaseFragment { 

  @Bind(R.id.fragment_work_pic_viewpager)
  ViewPager mFragmentWorkPicViewpager;
  @Bind(R.id.ll_dots)
  LinearLayout mLLDots;
//  @Bind(R.id.tv_desc)
//  TextView mTvDesc;
  @Bind(R.id.ll_kaoqing)
  LinearLayout mLlKaoqing;
  @Bind(R.id.ll_execute)
  LinearLayout mLlExecute;
  @Bind(R.id.ll_daohang)
  LinearLayout mLlDaohang;
  @Bind(R.id.ll_sudden)
  LinearLayout mLlSudden;
  @Bind(R.id.ll_policething)
  LinearLayout mLlPolicething;
  @Bind(R.id.ll_collect)
  LinearLayout mLlCollect;
  @Bind(R.id.ll_search)
  LinearLayout mLlSearch;
  @Bind(R.id.ll_noticevoice)
  LinearLayout mLlNoticevoice;
  @Bind(R.id.iv_book)
  ImageView mIvBook;
  @Bind(R.id.rl_shouce)
  RelativeLayout mRlShouce;
  @Bind(R.id.ibtn_yuan)
  ImageView mIbtnYuan;
  @Bind(R.id.ibtn_helpbook)
  ImageView mIbtnHelpbook; 

  private int[] imageResIds = {R.drawable.banner1,R.drawable.banner2};
  private String[] descs = {"武汉保安集团","智能巡逻系统"};
  private AutoScrollTask mAutoScrollTask; 

  @Override
  public void initData() {
    mFragmentWorkPicViewpager.addOnPageChangeListener(new OnPagerChangeListenerImp() {
      @Override
      public void onPageSelected(int position) {
        changeDotAndDesc(position);
      }
    });
    mFragmentWorkPicViewpager.setAdapter(new WorkFragmentBannerAdapter(imageResIds));
    initDot();
    changeDotAndDesc(0);  //默认选择第一页
    mFragmentWorkPicViewpager.setCurrentItem(mFragmentWorkPicViewpager.getAdapter().getCount() / 2); 

    if(mAutoScrollTask == null) {
      mAutoScrollTask = new AutoScrollTask();
      mAutoScrollTask.start();
    }
    //按下去停止轮播
    mFragmentWorkPicViewpager.setOnTouchListener(new View.OnTouchListener() {
      @Override
      public boolean onTouch(View view, MotionEvent motionEvent) {
        switch (motionEvent.getAction()) {
          case MotionEvent.ACTION_DOWN:
          case MotionEvent.ACTION_MOVE:
            mAutoScrollTask.stop();
            break;
          case MotionEvent.ACTION_UP:
            mAutoScrollTask.start();
            break;
        }
        return false;
      }
    });
  } 

  private void changeDotAndDesc(int position) {
    position = position % imageResIds.length;
//    mTvDesc.setText(descs[position]);
    for(int i = 0; i < mLLDots.getChildCount();i++) {
      ImageView iv_dot = (ImageView) mLLDots.getChildAt(i);
      iv_dot.setSelected(false);
      if(position == i) {
        iv_dot.setSelected(true);
      }
    }
  } 

  private void initDot() {
    for(int i = 0; i < imageResIds.length;i++) {
      int _5dp = dp2px(5);
      LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(_5dp,_5dp);
      params.leftMargin = _5dp;
      ImageView dot = new ImageView(mActivity);
      dot.setLayoutParams(params);
      dot.setBackgroundResource(R.drawable.selector_dot);
      mLLDots.addView(dot); 

    }
  } 

  public int dp2px(int dp) {
    float density = getResources().getDisplayMetrics().density;
    return (int) (dp * density + .5f);
  } 

  @Override
  public View initView() {
    // TODO: inflate a fragment view
    View rootView = View.inflate(mActivity,R.layout.fragment_work,null);
    ButterKnife.bind(this, rootView);
    return rootView;
  } 

  @Override
  public void onDestroyView() {
    super.onDestroyView();
    ButterKnife.unbind(this);
  } 

  @OnClick({R.id.rl_shouce,R.id.ibtn_yuan, R.id.ibtn_helpbook,R.id.ll_kaoqing, R.id.ll_execute, R.id.ll_daohang, R.id.ll_sudden, R.id.ll_policething, R.id.ll_collect, R.id.ll_search, R.id.ll_noticevoice})
  public void onClick(View view) {
    switch (view.getId()) {
      case R.id.ll_kaoqing:
        ToastUtil.showToast(mActivity,"考勤");
        break;
      case R.id.ll_execute:
        ToastUtil.showToast(mActivity,"勤务");
        break;
      case R.id.ll_daohang:
        ToastUtil.showToast(mActivity,"网店");
        break;
      case R.id.ll_sudden:
        ToastUtil.showToast(mActivity,"突发");
        break;
      case R.id.ll_policething:
        ToastUtil.showToast(mActivity,"警情");
        break;
      case R.id.ll_collect:
        ToastUtil.showToast(mActivity,"认证");
        break;
      case R.id.ll_search:
        ToastUtil.showToast(mActivity,"信息查询");
        break;
      case R.id.ll_noticevoice:
        ToastUtil.showToast(mActivity,"发布公告");
        break;
      case R.id.rl_shouce:
        ToastUtil.showToast(mActivity,"手册");
        break;
      case R.id.ibtn_yuan:
        ToastUtil.showToast(mActivity,"预案流程");
        break;
      case R.id.ibtn_helpbook:
        ToastUtil.showToast(mActivity,"帮助手册");
        break; 

    }
  } 

  private class AutoScrollTask implements Runnable{
    public void start() {
      stop();
      MyApplication.getMainThreadHandler().postDelayed(this,2000);
    } 

    public void stop() {
      MyApplication.getMainThreadHandler().removeCallbacks(this);
    } 

    @Override
    public void run() {
      int currentItem = mFragmentWorkPicViewpager.getCurrentItem();
      currentItem++;
      mFragmentWorkPicViewpager.setCurrentItem(currentItem);
      start();
    }
  }
}

这里轮播图下方的指示器(小点)或者图片描述都是可以加上的, 具体依据公司美工的要求即可
做了个按下去停止轮播的优化;  给viewpager设计点击监听,重写三个方法, 抬起则start(), 走run方法viewpager跳到下一页,并走AutoScrollTask中的start(),方法,主线程的Handler发送延时消息,则继续循环run方法,  实现轮播图的无线循环
对了,说下轮播图的PagerAdapter的写法

package com.hanzheng.znxl.adapter; 

import android.support.v4.view.PagerAdapter;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView; 

/**
 * Created by zmybi on 31/12/2016.
 */ 

public class WorkFragmentBannerAdapter extends PagerAdapter { 

 private int[] imageResIds; 

 public WorkFragmentBannerAdapter(int[] imageResIds) {
  this.imageResIds = imageResIds;
 } 

 @Override
 public int getCount() {
  return imageResIds.length * 1000000;
 } 

 @Override
 public boolean isViewFromObject(View view, Object object) {
  return view == object;
 } 

 @Override
 public Object instantiateItem(ViewGroup container, int position) {
  ImageView iv = new ImageView(container.getContext());
  position = position % imageResIds.length;
  iv.setBackgroundResource(imageResIds[position]);
  iv.setScaleType(ImageView.ScaleType.FIT_XY);
  container.addView(iv);
  return iv;
 } 

 @Override
 public void destroyItem(ViewGroup container, int position, Object object) {
  container.removeView((ImageView)object);
 }
}

这里返回一个很大的数,其实也没必要返回Integer.MAX_VALUE;  因为这样写的话还要对余数进行判断,让下方的Indicator和上方的图片切换保持一致,  当然,这里由于美工直接给的图,所以我直接放在工程下了,实际如果是从网上获取的,则使用Picasso或者Glide图片加载框架即可

至此,一个简单的图片轮播功能就已经实现了。