android应用程序获取互联网数据
这是android代码,用于从internet bu获取数据。当我运行此代码时,不会显示任何数据android应用程序获取互联网数据,android,Android,这是android代码,用于从internet bu获取数据。当我运行此代码时,不会显示任何数据 public class data { public String a()throws Exception { String data=null; BufferedReader b=null; try { HttpClient ob=new DefaultHttpClient
public class data
{
public String a()throws Exception
{
String data=null;
BufferedReader b=null;
try
{
HttpClient ob=new DefaultHttpClient();
URI website=new URI("http://www.mybringback.com");
HttpGet request=new HttpGet();
request.setURI(website);
HttpResponse response= ob.execute(request);
b=new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
StringBuffer bu=new StringBuffer ();
String i = null;
while((i=b.readLine())!=null)
{
bu.append(i);
}
b.close();
data=bu.toString();
return data;
}finally
{
if (b!=null)
{
try {
b.close();
return data;
}catch(Exception e)
{
e.printStackTrace();
}
}
}
}
}
我的主课
package com.example.hello;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import java.io.*;
import java.net.URI;
public class MyActivity extends Activity
{
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView m =(TextView)findViewById(R.id.de);
data ob=new data();
try {
String v= ob.a();
m.setText(v);
} catch (Exception e) {
e.printStackTrace();
}
}
}
我的xml文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ScrollView
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Hello World, MyActivity"
android:id="@+id/de">
</TextView>
</ScrollView>
</LinearLayout>
您正在ui线程上运行与网络相关的操作。可能正在获取
NetworkOnMainThreadException
。使用线程
或异步任务
如果网络操作持续时间较短,请使用Asynctask
您可以在onPostExecute
中将Asynctask
内部类作为更新ui
还要遵循java命名约定,重新命名变量和方法,这有助于可读性
例如:
public class MyActivity extends Activity
{
TextView m;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
m=(TextView)findViewById(R.id.de);
new TheTask().execute()
}
class TheTask extends AsyncTask<Void,Void,String>
{
String _response=null;
@Override
protected String doInBackground(Void... params) {
// TODO Auto-generated method stub
try
{
HttpClient ob=new DefaultHttpClient();
URI website=new URI("http://www.mybringback.com");
HttpGet request=new HttpGet();
request.setURI(website);
HttpResponse response= ob.execute(request);
HttpEntity resEntity = response.getEntity();
_response=EntityUtils.toString(resEntity);
}catch(Exception e)
{
e.printStackTrace();
}
return _response;
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
m.setText(result);
}
}
}
公共类MyActivity扩展活动
{
文本视图m;
@凌驾
创建时的公共void(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
m=(TextView)findViewById(R.id.de);
新建任务().execute())
}
类任务扩展异步任务
{
字符串_response=null;
@凌驾
受保护字符串doInBackground(无效…参数){
//TODO自动生成的方法存根
尝试
{
HttpClient ob=新的DefaultHttpClient();
URI网站=新的URI(“http://www.mybringback.com");
HttpGet请求=新建HttpGet();
setURI(网站);
HttpResponse response=ob.execute(请求);
HttpEntity当前性=response.getEntity();
_response=EntityUtils.toString(resEntity);
}捕获(例外e)
{
e、 printStackTrace();
}
返回响应;
}
@凌驾
受保护的void onPostExecute(字符串结果){
//TODO自动生成的方法存根
super.onPostExecute(结果);
m、 setText(结果);
}
}
}
logcat中是否有任何错误?如果您的API级别高于HONEYCOMB,您应该在另一个线程上运行所有网络内容,您必须在String v=ob.a()上获得异常
因为您不能在主线程上连接到Internet,所以必须使用AsycTask类或线程为执行+1操作,遵循java命名约定并重新命名变量和方法,这有助于可读性