Question

我想学习如何将数据从Android应用程序发送到网络服务器。我从教程中复制了一个代码，但是当我的应用程序尝试发送数据时，它只是崩溃了。 LogCat说：FatalException：main

我还没有网络服务器来发送数据，但我不认为这是问题所在。应用程序在执行任何操作之前崩溃。在你问之前，是的，我已经授予了互联网权限。

该计划如下：

package com.example.helloworld;

import java.io.IOException;
import org.apache.http.client.ClientProtocolException;


import java.util.ArrayList;
import java.util.List;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;


import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.message.BasicNameValuePair;

// import everything you need
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class MainActivity extends Activity {

Button sendButton;

EditText msgTextField;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    // load the layout
    setContentView(R.layout.activity_main);        

    // make message text field object
    msgTextField = (EditText) findViewById(R.id.msgTextField);
    // make send button object
    sendButton = (Button) findViewById(R.id.sendButton);

}

// this is the function that gets called when you click the button
public void send(View v)
{
    // get the message from the message text box
    String msg = msgTextField.getText().toString();  

    // make sure the fields are not empty
    if (msg.length()>0)
    {
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://yourwebsite.com/yourPhpScript.php");
     try {
       List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
       nameValuePairs.add(new BasicNameValuePair("id", "12345"));
       nameValuePairs.add(new BasicNameValuePair("message", msg));
       httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
       httpclient.execute(httppost);
       msgTextField.setText(""); // clear text box
     } catch (ClientProtocolException e) {
         // TODO Auto-generated catch block
     } catch (IOException e) {
         // TODO Auto-generated catch block
     }

    }
    else
    {
        // display message if text fields are empty
        Toast.makeText(getBaseContext(),"All field are required",Toast.LENGTH_SHORT).show();
    }

}

}

这是我正在遵循的教程：

http://webtutsdepot.com/2011/11/15/android-tutorial-how-to-post-data-from-an-android-app-to-a-website/

Answer 1

你不能在主线程中进行任何网络互动，你应该在其他线程中进行您可以AsyncTask课程进行网络互动

这是AsyncTask和互联网反应的简单示例Understanding AsyncTask – Once and Forever

请参阅AsyncTask文档

注意您的应用必须具有android.permission.INTERNET权限

Answer 2

您无法在主线程中发出Html请求。尝试asyncTask

public class AsyncDBTask extends AsyncTask<String, Void, String> {
    String message;
    public AsyncDBTask(String message){
        this.message=message;
    }

    @Override
    protected String  doInBackground(String... params) {
        rest=MySQLOperations.sendMessage(message);
        return null;
    }
    @Override
    protected void onPostExecute(String result) {

    }

    @Override
    protected void onPreExecute() {
    }

    @Override
    protected void onProgressUpdate(Void... values) {
    }

尝试将数据发送到Web服务器时，我的android应用程序崩溃了

2 个答案: