Android开发之利用Intent实现数据传递的方法

本文实例讲述了Android利用Intent实现数据传递的方法。分享给大家供大家参考，具体如下：

在Android开发过程中，很多人都熟悉Intent，这是个用于在多个View之间共享数据的类。本节主要讲述通过点选ListView中的文本，把文本中的URL加载到一个新的页面上，并且打印出来。为了方便，我先把前面一篇《Android开发之利用jsoup解析HTML页面的方法》的代码重新贴一下，因为在上一节后，代码做了少许修改：

try {    doc = Jsoup.parse(new URL("http://www.51yam.com"), 5000);    } catch (MalformedURLException e1) {      e1.printStackTrace();    } catch (IOException e1) {      e1.printStackTrace();    }    final List<Map<String, String>> list = new ArrayList<Map<String, String>>();    Elements es = doc.getElementsByClass("subnav");    for (int i=0;i<es.size();i++) {      Element e = es.get(i);      int count = e.getElementsByTag("a").size();      for(int j=0;j<count;j++)      {        Map<String, String> map = new HashMap<String, String>();        Element ex = e.getElementsByTag("a").get(j);        map.put("title", ex.text());        map.put("href", "http://www.51yam.com/"+ex.attr("href"));        list.add(map);      }    }    ListView listView = (ListView) findViewById(R.id.listView1);    listView.setAdapter(new SimpleAdapter(this, list, android.R.layout.simple_list_item_2,        new String[] { "title","href" }, new int[] {        android.R.id.text1,android.R.id.text2}));

实现的效果如下：

Android开发,数据传递

然后我们需要做的就是当点击ListView中的项目的时候，程序会将每个话题下面的URL链接发送到新的页面显示：

下面是当点击ListView项目的时候，利用Intent传递数据的方法：

listView.setOnItemClickListener(new OnItemClickListener(){  @Override  public void onItemClick(AdapterView<?> parent, View v, int position,long id) {    //Toast.makeText(getApplicationContext(), (TextView), duration)    System.out.println("position:"+position);    System.out.println("id:"+id);    //Toast.makeText(_GetWebResoureActivity.this, list.get(position).get("href"), Toast.LENGTH_SHORT).show();    Intent intent = new Intent(v.getContext(),topicdetails.class);    intent.putExtra("src", list.get(position).get("href"));    startActivityForResult(intent,0);  }});

在子页面“topicdetails.java”中，我们可以通过如下的方式来接收传递过来的值：

package com.android.web;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.widget.EditText;import java.lang.Object;public class topicdetails extends Activity {  private EditText editText;  @Override  protected void onCreate(Bundle savedInstanceState)  {    super.onCreate(savedInstanceState);    setContentView(R.layout.topiccontent);    editText = (EditText)this.findViewById(R.id.editText);    String srcUrl = getIntent().getStringExtra("src");    editText.setText(srcUrl);  }}

当然，一定不要忘记了在AndroidManifest.xml文件中添加Activity映射（黄色背景部分）：

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"  package="com.android.web"  android:versionCode="1"  android:versionName="1.0" >  <uses-sdk android:minSdkVersion="7" />  <!-- 加入访问网络的权限 -->  <uses-permission android:name="android.permission.INTERNET" />  <application    android:icon="@drawable/ic_launcher"    android:label="@string/app_name" >    <activity      android:label="@string/app_name"      android:name="._GetWebResoureActivity" >      <intent-filter >        <action android:name="android.intent.action.MAIN" />        <category android:name="android.intent.category.LAUNCHER" />      </intent-filter>    </activity>    <activity android:name=".topicdetails"></activity>  </application></manifest>

这样当一切工作准备完毕后，运行程序，点击ListView 的Item，我们成功地跳转到了子页面：

Android开发,数据传递

以下是所有的源码：

主页面源码：

package com.android.web;import java.io.BufferedInputStream;import java.io.IOException;import java.io.InputStream;import java.net.MalformedURLException;import java.net.URL;import java.net.URLConnection;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import java.lang.Object;import org.apache.http.util.ByteArrayBuffer;import org.apache.http.util.EncodingUtils;import org.jsoup.Jsoup;import org.jsoup.nodes.Document;import org.jsoup.nodes.Element;import org.jsoup.select.Elements;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.ListView;import android.widget.SimpleAdapter;import android.widget.Toast;public class _GetWebResoureActivity extends Activity {  Document doc;  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main);    findViewById(R.id.button1).setOnClickListener(new OnClickListener() {      @Override      public void onClick(View v) {        load();      }    });  }  protected void load() {    try {      doc = Jsoup.parse(new URL("http://www.51yam.com"), 5000);    } catch (MalformedURLException e1) {      e1.printStackTrace();    } catch (IOException e1) {      e1.printStackTrace();    }    final List<Map<String, String>> list = new ArrayList<Map<String, String>>();    Elements es = doc.getElementsByClass("subnav");    for (int i=0;i<es.size();i++) {      Element e = es.get(i);      int count = e.getElementsByTag("a").size();      for(int j=0;j<count;j++)      {        Map<String, String> map = new HashMap<String, String>();        Element ex = e.getElementsByTag("a").get(j);        map.put("title", ex.text());        map.put("href", "http://www.51yam.com/"+ex.attr("href"));        list.add(map);      }    }    ListView listView = (ListView) findViewById(R.id.listView1);    listView.setAdapter(new SimpleAdapter(this, list, android.R.layout.simple_list_item_2,        new String[] { "title","href" }, new int[] {        android.R.id.text1,android.R.id.text2    }));    listView.setOnItemClickListener(new OnItemClickListener(){      @Override      public void onItemClick(AdapterView<?> parent, View v, int position,long id) {        //Toast.makeText(getApplicationContext(), (TextView), duration)        System.out.println("position:"+position);        System.out.println("id:"+id);        //Toast.makeText(_GetWebResoureActivity.this, list.get(position).get("href"), Toast.LENGTH_SHORT).show();        Intent intent = new Intent(v.getContext(),topicdetails.class);        intent.putExtra("src", list.get(position).get("href"));        startActivityForResult(intent,0);      }    });  }  /**   * @param urlString   * @return   */  public String getHtmlString(String urlString) {    try {      URL url = null;      url = new URL(urlString);      URLConnection ucon = null;      ucon = url.openConnection();      InputStream instr = null;      instr = ucon.getInputStream();      BufferedInputStream bis = new BufferedInputStream(instr);      ByteArrayBuffer baf = new ByteArrayBuffer(500);      int current = 0;      while ((current = bis.read()) != -1) {        baf.append((byte) current);      }      return EncodingUtils.getString(baf.toByteArray(), "gbk");    } catch (Exception e) {      return "";    }  }}

子页面源码：

package com.android.web;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.widget.EditText;import java.lang.Object;public class topicdetails extends Activity {  private EditText editText;  @Override  protected void onCreate(Bundle savedInstanceState)  {    super.onCreate(savedInstanceState);    setContentView(R.layout.topiccontent);    editText = (EditText)this.findViewById(R.id.editText);    String srcUrl = getIntent().getStringExtra("src");    editText.setText(srcUrl);  }}