在这个案例中展示的新闻列表,使用到ListView控件,然后在适配器中添加多种布局效果,这里通过重写BaseAdapter类中的
getViewType()和getItemViewType()来做判断,指定ListView列表中指定位置的item加载对应的布局,在
getView中返回对应的视图,之前由于不清楚getViewTypeCount()和getItemViewType()方法,使用得比较少,一直以
为需要添加多个适配器,现在看来当时的想法说明自己见识还不够,哈哈。
第一步:创建放置ListView控件的news_list_listView.xml布局,如下
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<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" > <ListView android:id="@+id/news_list_more_layout_listView" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" /> </RelativeLayout> |
第二步:定义不要在ListView控件中展示新闻列表的布局 效果,在上面的案例中,banner是一张图片和新闻标题,中间是新闻标题、新闻概要和图片,最后是新闻标题和三张新闻图片,这里三个布局分别命名 为:news_banner_item.xml,news_list_item.xml,news_three_img_item.xml
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<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="150dp" > <ImageView android:id="@+id/model_news_title_iv" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_alignParentLeft="true" android:src="@drawable/demo" android:scaleType="fitXY" android:contentDescription="@string/news_content_description"/> <TextView android:id="@+id/model_news_title_tv" android:layout_width="match_parent" android:layout_height="25dp" android:layout_alignBottom="@+id/model_news_title_iv" android:layout_alignParentLeft="true" android:background="@color/list_item_bg_selector" android:gravity="center_vertical" android:paddingLeft="10dp" android:text="@string/display_news" /> </RelativeLayout> |
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<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" > <ImageView android:id="@+id/news_list_profile_image_iv" style="@style/weixin_news_list_img_c" android:layout_marginRight="@dimen/shadow_width" android:contentDescription="@string/news_each_info" android:src="@drawable/ic_launcher" android:scaleType="fitXY" /> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_centerInParent="true" android:layout_marginLeft="@dimen/shadow_width" android:layout_toLeftOf="@+id/news_list_profile_image_iv" android:orientation="vertical" android:id="@+id/news_list_item_ll" > <TextView android:id="@+id/news_title_tv" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/rec_tone" android:textSize="@dimen/list_cat_size" android:textColor="@color/text_black_title" /> <TextView android:id="@+id/news_overview_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/news_overview_info" android:textColor="@color/text_gray_title" android:textSize="@dimen/list_dis_tv_size" /> </LinearLayout> <View android:layout_width="match_parent" android:layout_height="0dp" android:background="@color/list_item_bg_selector" android:layout_below="@+id/news_list_item_ll" android:layout_marginTop="4dp"/> </RelativeLayout> |
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<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="120dp" > <RelativeLayout android:id="@+id/news_more_img_rl" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@+id/news_list_item_text_iv"> <LinearLayout android:id="@+id/news_horizontal_ll" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" > <ImageView android:id="@+id/news_list_item_img_one_iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="5dp" android:layout_weight="1" android:src="@drawable/ic_launcher" /> <ImageView android:id="@+id/news_list_item_img_two_iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="5dp" android:layout_weight="1" android:src="@drawable/ic_launcher" /> <ImageView android:id="@+id/news_list_item_img_three_iv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="5dp" android:layout_weight="1" android:src="@drawable/ic_launcher" /> </LinearLayout> </RelativeLayout> <TextView android:id="@+id/news_list_item_text_iv" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:text="@string/display_news" android:textColor="@color/text_black_title" android:textSize="@dimen/list_cat_size" /> </RelativeLayout> |
第三步:在NewsMainActivity中获取布局 news_list_listview.xml中的ListView控件,然后添加ListView的适配器 MyNewsBaseAdapter,MyNewsBaseAdapter继承BaseAdapter,重写getViewType、 getItemViewType、getItem、getItemId、getCount和getView方法,其中重点是getViewType和 getItemViewType方法,通过这两个方法判断需要加载的布局,getViewTypeCount返回布局视图数 量,getItemViewType方法加载布局视图。
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@Override public int getItemViewType( int position) { int p = position; if (p == 0 ) { return TYPE_BANNER; //position是ListView中item的ID,指定ID为0的item,加载news_banner_item.xml布局 } else if (p > 0 && 0 == p % 4 ) { return TYPE_THREE_IMG_ITEM; //加载news_three_img_item.xml } else { return TYPE_COMMON_LIST_ITEM; //加载news_list_item.xml,news_three_img_item.xml } } @Override public int getViewTypeCount() { return 3 ; } |
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@Override public View getView( int position, View convertView, ViewGroup parent) { ViewHolder viewHolder = null ; ViewHolder2 viewHolder2 = null ; ViewHolder3 viewHolder3 = null ; int type = getItemViewType(position); //获取指定的布局类型 inflater = (LayoutInflater) context .getSystemService(Context.LAYOUT_INFLATER_SERVICE); //布局加载器对象 if (convertView == null ) { switch (type) { case TYPE_BANNER: convertView = inflater.inflate(R.layout.img_text_banner_item, parent, false ); viewHolder = new ViewHolder(); viewHolder.bannerImg = (ImageView) convertView .findViewById(R.id.model_news_title_iv); viewHolder.bannerTitle = (TextView) convertView .findViewById(R.id.model_news_title_tv); convertView.setTag(viewHolder); break ; case TYPE_COMMON_LIST_ITEM: convertView = inflater.inflate(R.layout.news_list_item, parent, false ); viewHolder2 = new ViewHolder2(); viewHolder2.commonImg = (ImageView) convertView .findViewById(R.id.news_list_profile_image_iv); viewHolder2.overviewTV = (TextView) convertView .findViewById(R.id.news_overview_tv); viewHolder2.titleTV = (TextView) convertView .findViewById(R.id.news_title_tv); convertView.setTag(viewHolder2); break ; case TYPE_THREE_IMG_ITEM: convertView = inflater.inflate(R.layout.more_img_text_item, parent, false ); viewHolder3 = new ViewHolder3(); viewHolder3.titleTV = (TextView) convertView .findViewById(R.id.news_list_item_text_iv); viewHolder3.imgOne = (ImageView) convertView .findViewById(R.id.news_list_item_img_one_iv); viewHolder3.imgTwo = (ImageView) convertView .findViewById(R.id.news_list_item_img_two_iv); viewHolder3.imgThree = (ImageView) convertView .findViewById(R.id.news_list_item_img_three_iv); convertView.setTag(viewHolder3); break ; } } else { switch (type) { case TYPE_BANNER: viewHolder = (ViewHolder) convertView.getTag(); break ; case TYPE_COMMON_LIST_ITEM: viewHolder2 = (ViewHolder2) convertView.getTag(); break ; case TYPE_THREE_IMG_ITEM: viewHolder3 = (ViewHolder3) convertView.getTag(); break ; } } // 填充数据到指定的布局文件中 switch (type) { case TYPE_BANNER: viewHolder.bannerImg.setImageResource(R.drawable.demo); //图片从资源中获取 viewHolder.bannerTitle.setText(entryList.get(position) //entryList是存放新闻消息实体List对象,获取新闻标题 .getFull_title()); break ; case TYPE_COMMON_LIST_ITEM: viewHolder2.commonImg.setImageResource(R.drawable.demo); viewHolder2.overviewTV .setText(entryList.get(position).getContent()); //获取新闻内容 viewHolder2.titleTV .setText(entryList.get(position).getFull_title()); //获取新闻内容 break ; case TYPE_THREE_IMG_ITEM: viewHolder3.titleTV .setText(entryList.get(position).getFull_title()); viewHolder3.imgOne.setImageResource(R.drawable.demo); viewHolder3.imgTwo.setImageResource(R.drawable.demo); viewHolder3.imgThree.setImageResource(R.drawable.demo); break ; default : break ; } return convertView; } |
这里展示部分的源码,完整的源码可以点击这里下载