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。

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