ANDROID 开发一个新闻阅读器之新闻列表

1 2   <? xml version="1.0" encoding="utf-8" ?> 3   < LinearLayout xmlns:android ="http://schemas.android.com/apk/res/android" 4 android:orientation ="vertical" 5 android:layout_width ="fill_parent" 6 android:layout_height ="fill_parent" 7 android:background ="@color/white" > 8 //按钮栏布局，上篇课程已经讲解过，这里不再多做介绍 9 < RelativeLayout android:id ="@+id/result_RelativeLayout01" 10 android:layout_width ="fill_parent" 11 android:layout_height ="wrap_content" 12 android:background ="@color/yellow" > 13 < Button android:id ="@+id/result_back" //定义了一个新的 ID result_back 14 android:layout_width ="wrap_content" 15 android:layout_height ="wrap_content" 16 android:layout_alignParentLeft ="true" 17 android:paddingLeft ="2dip" 18 android:text ="@string/back" /> 19 //定义了一个新的 ID result_collection 20   < Button android:id ="@+id/result_collection" 21 android:layout_width ="wrap_content" 22 android:layout_height ="wrap_content" 23 android:layout_alignParentRight ="true" 24 android:paddingRight ="2dip" 25 android:text ="@string/collection" /> 26 </ RelativeLayout > 27 28 // 开始定义ListView，给ListView的最外层定义一个LinearLayout 布局 29 < LinearLayout android:id ="@+id/result_LinearLayout01" 30 android:layout_width ="fill_parent" 31 android:layout_height ="fill_parent" 32 android:padding ="5dip" 33 android:orientation ="vertical" > 34 // 定义一个RelativeLayout 布局 35 < RelativeLayout android:id ="@+id/android:empty" 36 android:layout_width ="fill_parent" 37 android:layout_height ="wrap_content" 38 xmlns:android ="http://schemas.android.com/apk/res/android" > 39 //定义一个TextView 用来显示诸如:数据读取中，不存在新闻数据　这类让用户了解现在软件运行状态的信息 40 < TextView android:id ="@+id/newsResultListEmptyText" 41 android:layout_width ="fill_parent" 42 android:gravity ="center" 　//布局居中 43 android:layout_height ="100dip" 44 //对应上层布局居中 45 android:layout_centerInParent ="true" 46 android:text ="@string/wait_loading" //默认显示内容 47 android:textColor ="@color/black" //字体颜色 48 android:textStyle ="bold" > //字体样式 49 </ TextView > 50 </ RelativeLayout > 51 // 定义ListView 控件，ID 设为 newsResultList 52 < ListView android:id ="@+id/newsResultList" 53 android:cacheColorHint ="#00000000" //这个属性可以有效防止滑动过程中，ITEM 颜色变黑 54 android:dividerHeight ="1dip" //2个ITEM 之间的间隔距离 55 android:scrollbars ="none" //是否显示滑动条，默认是显示，我们这里设置成不显示 56 android:divider ="@color/semi_black" //2个ITEM 之间间隔条的颜色 57 android:layout_width ="fill_parent" 58 android:layout_height ="fill_parent" > 59 </ ListView > 60 </ LinearLayout > 61 62   </ LinearLayout > 63

1 <? xml version="1.0" encoding="utf-8" ?> 2   < LinearLayout xmlns:android ="http://schemas.android.com/apk/res/android" 3 android:orientation ="horizontal" //注意这里定义的是 horizontal 的布局，也就是横向的 4 android:layout_width ="fill_parent" 5 android:layout_height ="50dip" 6 android:background ="@color/white" > 7 //定义一个ImageView ID 为 result_newsImg 8 < ImageView android:id ="@+id/result_newsImg" 9 android:layout_width ="wrap_content" 10 android:layout_height ="wrap_content" 11 android:layout_gravity ="center_vertical" //设置为布局剧中 12 android:src ="@drawable/news_icon" /> //图片指向的目录 13 //定义一个 TextView ID 为 result_newsImg 14 < TextView android:id ="@+id/result_newsTitle" 15 android:layout_width ="fill_parent" 16 android:layout_height ="wrap_content" 17 android:layout_gravity ="center_vertical" //设置为布局剧中 18 android:padding ="5dip" 19 android:textSize ="15px" 20 android:textColor ="@color/black" 21 android:textStyle ="bold" /> 22   </ LinearLayout >

 

1 public String newsType = "0"; 2   public Context mContext; 3 4 public void onCreate(Bundle savedInstanceState) { 5 super.onCreate(savedInstanceState); 6 setContentView(R.layout.news_result_list); 7 8 mContext = newsResultListActivity. this; 9 10 Intent aIntent = getIntent(); 11 Bundle aBundle = aIntent.getExtras(); 12 if(aBundle != null){ 13 // 获取上一个Activity 传递过来的新闻类型参数 14   newsType = aBundle.getString(MyNewsReaderConstant.MAIN_NEWS_TYPE); 15 } 16 17 // 显示一个loading框 18   startLoadingDialog(); 19 20 // 获取页面上定义的控件资源，包括listview 21   findView(); 22 23 // 开启一个线程用来获取网络新闻数据 24   Thread webThread = new Thread( new getWebData()); 25 webThread.start(); 26 }

1 public ProgressDialog pd; 2 3   public void startLoadingDialog(){ 4 pd = ProgressDialog.show(newsResultListActivity. this, null, MyNewsReaderConstant.PROGRESS_ALERT_LOADING, true, true); 5 }

1 public Button result_back, result_collection; 2   // 用来显示无新闻记录，或者请用户等待 一类的提示信息 3   public TextView newsResultListEmptyText; 4   public ListView newsResultList; // 页面的ListView控件 5   6   public void findView(){ 7 8 result_back = (Button) this.findViewById(R.id.result_back); 9 result_collection = (Button) this.findViewById(R.id.result_collection); 10 newsResultListEmptyText = (TextView) this.findViewById(R.id.newsResultListEmptyText); 11 newsResultList = (ListView) this.findViewById(R.id.newsResultList); 12 13 }

1 protected static final int threadS1 = 0x2311; 2   protected static final int threadF1 = 0x2312; 3   public List<newsDataTO> dataList; // 存放数据的List 4   public getWebDataHelperI gwdhI; // 实现网络功能的接口 5   6   public class getWebData implements Runnable{ 7 8 @Override 9 public void run() { 10 Message m1 = new Message(); 11 Message m2 = new Message(); 12 m1.what = threadS1; 13 m2.what = threadF1; 14 15 dataList = new ArrayList<newsDataTO>(); 16 boolean sendErrorMsg = false; 17 18 // searchValues 数组，用来存放网络查询参数 19   String[] searchColumns = {"type"}; 20 String[] searchValues = {newsType}; 21 // 实例化这个借口 22   gwdhI = new getWebDataHelperImpl(); 23 // 调用该接口的实现方法,把 searchColumnns, searchValues作为参数 24   dataList = gwdhI.getNewsResultListByType(searchColumns, searchValues); 25 // 如果返回的List为空，发送错误消息 26   if(dataList == null || dataList.size() == 0){ 27 messageListener.sendMessage(m2); 28 return; 29 } 30 // List不为空，发送正确消息 31   messageListener.sendMessage(m1); 32 } 33 34 }

1 Handler messageListener = new Handler(){ 2 3 public void handleMessage(Message msg){ 4 switch(msg.what){ 5 case threadS1: 6 pd.dismiss(); // 关闭loading框 7   displayNewsResult(); // 显示新闻列表 8   break; 9 case threadF1: 10 pd.dismiss(); // 关闭loading框 11 // 显示未能查询到记录的信息 12   newsResultListEmptyText.setVisibility(View.VISIBLE); 13 // 显示提示信息，该信息定义在string.xml中的serverConnectErrorMsg newsResultListEmptyText.setText(getResources().getString(R.string.serverConnectErrorMsg)); 14   break; 15 } 16 } 17 };

1 public void displayNewsResult(){ 2 // 当有返回新闻数据时，提示信息不用显示 设置为不可见，这样用户就看不到页面上 '请等待' 这些提示 3   newsResultListEmptyText.setVisibility(View.GONE); 4 // 自定义一个 Adapter 5   newsResultListAdapter newsResultAdapter = new newsResultListAdapter(dataList, mContext); 6 // 将自定义的Adapter set进newsResultList，该List就是页面上的 ListView控件 7  newsResultList.setAdapter(newsResultAdapter); 8 // 给ListView控件添加 onItemClickListener 事件，使用户点击ITEM 的时候能触发事件 9   newsResultList.setOnItemClickListener( new OnItemClickListener(){ 10 @Override 11 public void onItemClick(AdapterView<?> arg0, View arg1, 12 int arg2, long arg3) { 13 // TODO Auto-generated method stub 14   15 } 16 17 }); 18 }

1 public class newsDataTO { 2 private long id; // 唯一的ID 3   private long newsId; // 新闻的唯一的ID 4   private String newsType; // 新闻的类型 5   private String newsTitle; // 新闻的标题 6   private String newsContent; // 新闻的内容 7   8 public long getId() { 9 return id; 10 } 11 public void setId( long id) { 12 this.id = id; 13 } 14 public long getNewsId() { 15 return newsId; 16 } 17 public void setNewsId( long newsId) { 18 this.newsId = newsId; 19 } 20 public String getNewsType() { 21 return newsType; 22 } 23 public void setNewsType(String newsType) { 24 this.newsType = newsType; 25 } 26 public String getNewsTitle() { 27 return newsTitle; 28 } 29 public void setNewsTitle(String newsTitle) { 30 this.newsTitle = newsTitle; 31 } 32 public String getNewsContent() { 33 return newsContent; 34 } 35 public void setNewsContent(String newsContent) { 36 this.newsContent = newsContent; 37 } 38 39 }

1 // searchValues 数组，用来存放网络查询参数 2   String[] searchColumns = {"type"}; 3 String[] searchValues = {newsType};

1 import java.util.List; 2   import com.thinkland.demo.mnr.data.newsDataTO; 3 4   public interface getWebDataHelperI { 5 6 public List<newsDataTO> getNewsResultListByType(String[] searchColumns, String[] searchValues); 7 8 }

1 Map searchMap = new HashMap(); 2 // 如果查询字段存放数组内有值，将 hashMap 的键设置成 查询的字段名字 3   if(searchColumns != null){ 4 for( int i = 0; i< searchColumns.length; i++){ 5 searchMap.put(searchColumns[i], ""); 6 } 7 } 8 // 如果查询具体内容存放数组有值，将该值按顺序放入searchMap 的值中 9   if(searchValues != null){ 10 for( int ii = 0; ii< searchValues.length; ii++){ 11 // 这里防止 value 超出了searchColumns 数组的范围 12   if(ii <= searchColumns.length){ 13 searchMap.put(searchColumns[ii], searchValues[ii]); 14 } 15 } 16 } 17 18 StringBuffer sb = new StringBuffer(); 19 sb.append(""); 20 Iterator it = searchMap.entrySet().iterator(); 21 while (it.hasNext()) { 22 Entry entry = (java.util.Map.Entry) it.next(); 23 sb.append("&"); 24 sb.append(entry.getKey()); // 返回与此项对应的键 25   sb.append("="); 26 sb.append(entry.getValue()); // 返回与此项对应的值 27   28 } 29 String searchUrlValue = sb.toString(); 30 if(searchUrlValue != null && !"".equals(searchUrlValue)){ 31 searchUrlValue = searchUrlValue.substring(1); // 跳过开头的&符号，最后产生的查询参数因该是类似: parameter1=a&parameter2=b 32   } 33

1 URL connectUrl = new URL(“http: // pic.think-land.com/xmlall.php?type=4”); 2   // 返回一个 URLConnection 对象，它表示到 URL 所引用的远程对象的连接。 3  URLConnection uc = connectUrl.openConnection(); 4   // 打开的连接读取的输入流。 5  InputStream is = uc.getInputStream();

1 2 DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance(); 3 DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder(); 4 5 ByteArrayOutputStream baos = new ByteArrayOutputStream(); 6 int i=-1; 7 while((i=is.read())!=-1){ 8 baos.write(i); 9 } 10 String returnIs = baos.toString().trim(); 11   // Log.v("test", "-------------------- parseXML_rg returnIs is : \n" + returnIs); 12   InputStream iis = new ByteArrayInputStream(returnIs.getBytes()); 13 14 15 16 Document doc = docBuilder.parse(iis); 17 doc.getDocumentElement ().normalize (); 18 19 NodeList listOfTeams = doc.getElementsByTagName("row"); 20 21 for( int s=0; s<listOfTeams.getLength() ; s++){ 22 Node firstTeamNode = listOfTeams.item(s); 23 if(firstTeamNode.getNodeType() == Node.ELEMENT_NODE){ 24 25 Element firstTeamElement = (Element)firstTeamNode; 26 // 实例化一个新的newsDataTO 27   newsDataTO ndTO = new newsDataTO(); 28 // 通过节点获取到值，新闻的ID 29   String id = getValueByElement(firstTeamElement, "id"); 30 // 通过节点获取到值，新闻的标题 31   String newsTitle = getValueByElementAfterUtf(firstTeamElement,"title"); 32 // 保存进数据结构，通过set方法 33   ndTO.setId(Integer.parseInt(id)); 34 ndTO.setNewsId(Integer.parseInt(id)); 35 ndTO.setNewsTitle(newsTitle); 36 // 将该数据结构添加进list 37   dataList.add(ndTO); 38 } 39 }

1 /** 2 * 根据节点获取内容 3 * @param element 4 * @param tagName 5 * @return String 6 */ 7 private String getValueByElement(Element element, String tagName){ 8 String returnValue = ""; 9 10 NodeList firstNameList = element.getElementsByTagName(tagName); 11 Element firstNameElement = (Element)firstNameList.item(0); 12 NodeList textList = firstNameElement.getChildNodes(); 13 if(textList != null && (Node)textList.item(0)== null){ 14 returnValue = ""; 15 } else if(textList != null && ((Node)textList.item(0)).getNodeValue() != null){ 16 returnValue = ((Node)textList.item(0)).getNodeValue().trim(); 17 } 18 return returnValue; 19 } 20 21 /** 22 * 根据节点获取内容，并对获取的值做 UTF-8 的编码处理，一般针对中文 23 * @param element 节点对象 24 * @param tagName 节点名字 25 * @return String 26 */ 27 private String getValueByElementAfterUtf(Element element, String tagName){ 28 String returnValue = ""; 29 NodeList firstNameList = element.getElementsByTagName(tagName); 30 Element firstNameElement = (Element)firstNameList.item(0); 31 NodeList textList = firstNameElement.getChildNodes(); 32 if(textList != null && ((Node)textList.item(0)).getNodeValue() != null){ 33 try { 34   // 对该节点下的字节流进行 utf-8 解码 35   returnValue = new String( ((Node)textList.item(0)).getNodeValue().getBytes(), "utf-8"); 36 } catch (UnsupportedEncodingException e) { 37 e.printStackTrace(); 38 } catch (DOMException e) { 39 e.printStackTrace(); 40 } 41 } 42 return returnValue; 43 }

1 import java.io.ByteArrayInputStream; 2   import java.io.ByteArrayOutputStream; 3   import java.io.InputStream; 4   import java.io.UnsupportedEncodingException; 5   import java.net.URL; 6   import java.util.ArrayList; 7   import java.util.HashMap; 8   import java.util.Iterator; 9   import java.util.List; 10   import java.util.Map; 11   import java.util.Map.Entry; 12 13   import javax.xml.parsers.DocumentBuilder; 14   import javax.xml.parsers.DocumentBuilderFactory; 15 16   import org.w3c.dom.DOMException; 17   import org.w3c.dom.Document; 18   import org.w3c.dom.Element; 19   import org.w3c.dom.Node; 20   import org.w3c.dom.NodeList; 21   import org.xml.sax.SAXException; 22   import org.xml.sax.SAXParseException; 23 24   import android.util.Log; 25 26   import com.thinkland.demo.mnr.data.newsDataTO; 27 28   public class getWebDataHelperImpl implements getWebDataHelperI{ 29 30 public List<newsDataTO> getNewsResultListByType(String[] searchColumns, String[] searchValues) { 31 32 // 测试用URL 地址 33   String netUrl = "http://pic.think-land.com/xmlall.php?"; 34 35 try{ 36 Map searchMap = new HashMap(); 37 // 如果查询字段存放数组内有值，将 hashMap 的键设置成 查询的字段名字 38   if(searchColumns != null){ 39 for( int i = 0; i< searchColumns.length; i++){ 40 searchMap.put(searchColumns[i], ""); 41 } 42 } 43 // 如果查询具体内容存放数组有值，将该值按顺序放入searchMap 的值中 44   if(searchValues != null){ 45 for( int ii = 0; ii< searchValues.length; ii++){ 46 // 这里防止 value 超出了searchColumns 数组的范围 47   if(ii <= searchColumns.length){ 48 searchMap.put(searchColumns[ii], searchValues[ii]); 49 } 50 } 51 } 52 53 StringBuffer sb = new StringBuffer(); 54 sb.append(""); 55 Iterator it = searchMap.entrySet().iterator(); 56 while (it.hasNext()) { 57 Entry entry = (java.util.Map.Entry) it.next(); 58 sb.append("&"); 59 sb.append(entry.getKey()); // 返回与此项对应的键 60   sb.append("="); 61 sb.append(entry.getValue()); // 返回与此项对应的值 62   63 } 64 String searchUrlValue = sb.toString(); 65 if(searchUrlValue != null && !"".equals(searchUrlValue)){ 66 searchUrlValue = searchUrlValue.substring(1); // 跳过开头的&符号，最后产生的查询参数因该是类似: parameter1=a&parameter2=b 67   } 68 Log.v("getWebDataHelperImp", "---------------------- searchUrlValue : " + searchUrlValue); 69 return netXMLPrase(netUrl + searchUrlValue); 70 71 } catch(Exception e){ 72 e.printStackTrace(); 73 } 74 75 return null; 76 } 77 78 public List netXMLPrase(String uriStr) throws Exception{ 79 try{ 80 List dataList = new ArrayList<newsDataTO>(); 81 82 URL connectUrl = new URL(uriStr); 83 // 返回一个 URLConnection 对象，它表示到 URL 所引用的远程对象的连接。 84  URLConnection uc = connectUrl.openConnection(); 85   // 打开的连接读取的输入流。 86  InputStream is = uc.getInputStream(); 87 if(is == null){ 88 throw new Exception("netXMLPraseComicName - The inputStream is null"); 89 } 90 91 DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance(); 92 DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder(); 93 94 ByteArrayOutputStream baos = new ByteArrayOutputStream(); 95 int i=-1; 96 while((i=is.read())!=-1){ 97 baos.write(i); 98 } 99 String returnIs = baos.toString().trim(); 100   // Log.v("test", "-------------------- parseXML_rg returnIs is : \n" + returnIs); 101   InputStream iis = new ByteArrayInputStream(returnIs.getBytes()); 102 103 104 105 Document doc = docBuilder.parse(iis); 106 doc.getDocumentElement ().normalize (); 107 108 NodeList listOfTeams = doc.getElementsByTagName("row"); 109 110 for( int s=0; s<listOfTeams.getLength() ; s++){ 111 Node firstTeamNode = listOfTeams.item(s); 112 if(firstTeamNode.getNodeType() == Node.ELEMENT_NODE){ 113 114 Element firstTeamElement = (Element)firstTeamNode; 115 116 newsDataTO ndTO = new newsDataTO(); 117 118 String id = getValueByElement(firstTeamElement, "id"); 119 String newsTitle = getValueByElementAfterUtf(firstTeamElement,"title"); 120 121 ndTO.setId(Integer.parseInt(id)); 122 ndTO.setNewsId(Integer.parseInt(id)); 123 ndTO.setNewsTitle(newsTitle); 124 125 dataList.add(ndTO); 126 } 127 } 128 129 return dataList; 130 131 } catch (SAXParseException err) { 132 throw new Exception(err); 133 } catch (SAXException e) { 134 Exception x = e.getException(); 135 ((x == null) ? e : x).printStackTrace(); 136 throw new Exception(e); 137 } catch (Exception t) { 138 t.printStackTrace(); 139 throw new Exception(t); 140 } 141 } 142 143 144 /** 145 * 根据节点获取内容 146 * @param element 147 * @param tagName 148 * @return String 149 */ 150 private String getValueByElement(Element element, String tagName){ 151 String returnValue = ""; 152 153 NodeList firstNameList = element.getElementsByTagName(tagName); 154 Element firstNameElement = (Element)firstNameList.item(0); 155 NodeList textList = firstNameElement.getChildNodes(); 156 if(textList != null && (Node)textList.item(0)== null){ 157 returnValue = ""; 158 } else if(textList != null && ((Node)textList.item(0)).getNodeValue() != null){ 159 returnValue = ((Node)textList.item(0)).getNodeValue().trim(); 160 } 161 return returnValue; 162 } 163 164 /** 165 * 根据节点获取内容，并对获取的值做 UTF-8 的编码处理，一般针对中文 166 * @param element 167 * @param tagName 168 * @return String 169 */ 170 private String getValueByElementAfterUtf(Element element, String tagName){ 171 String returnValue = ""; 172 173 NodeList firstNameList = element.getElementsByTagName(tagName); 174 Element firstNameElement = (Element)firstNameList.item(0); 175 NodeList textList = firstNameElement.getChildNodes(); 176 if(textList != null && ((Node)textList.item(0)).getNodeValue() != null){ 177 try { 178 returnValue = new String( ((Node)textList.item(0)).getNodeValue().getBytes(), "utf-8"); 179 } catch (UnsupportedEncodingException e) { 180 e.printStackTrace(); 181 } catch (DOMException e) { 182 e.printStackTrace(); 183 } 184 } 185 return returnValue; 186 } 187 188 189 }

1 import java.util.List; 2   import com.thinkland.demo.mnr.R; 3   import com.thinkland.demo.mnr.data.newsDataTO; 4   import android.content.Context; 5   import android.view.LayoutInflater; 6   import android.view.View; 7   import android.view.ViewGroup; 8   import android.widget.BaseAdapter; 9   import android.widget.TextView; 10 11   public class newsResultListAdapter extends BaseAdapter{ 12 13 private String TAG = "newsResultListAdapter"; 14 private LayoutInflater mInflater; 15 private List<newsDataTO> item; 16 private Context context; 17 18 public newsResultListAdapter(List<newsDataTO> item, Context context) { 19 super(); 20 // 从给定的context中获取 LayoutInflater 21   mInflater = LayoutInflater.from(context); 22 this.item = item; 23 this.context = context; 24 } 25 26 // item 的数量 27   public int getCount() { 28 return item.size(); 29 } 30 31 // 获取item的实例对象，参数position通常都是指当前item的id 32   public newsDataTO getItem( int position) { 33 return item.get(position); 34 } 35 36 // 获取当前item 的id 37   public long getItemId( int position) { 38 return position; 39 } 40 41 42 // 实例化这个adapter时传入要显示的数据，然后用getView来显示每一个ListView的item 43   public View getView( int position, View convertView, ViewGroup parent) { 44 // 将 news_result_list_item 转换为 view 45   if(convertView == null) { 46 convertView = mInflater.inflate(R.layout.news_result_list_item, null); 47 } 48 // 获取 view里的 TextView　 49   TextView newsTitle = (TextView) convertView.findViewById(R.id.result_newsTitle); 50 // 获取对应的 newsDataTO 51   newsDataTO newsDatato = (newsDataTO)getItem(position); 52 // 将存放在 该数据结构中的 新闻标题 在页面布局上显示 53   newsTitle.setText(newsDatato.getNewsTitle()); 54 55 return convertView; 56 } 57 58 } 59

1 newsResultListAdapter newsResultAdapter = new newsResultListAdapter(dataList, mContext); 2 newsResultList.setAdapter(newsResultAdapter);

1 < activity android:name =".newsResultListActivity" />

1 < uses-permission android:name ="android.permission.INTERNET" />