我正在尝试从 Mainactivity.java 调用另一个名为 HttpUtilityTester.java 的类。实际上，我想通过单击按钮从 HttpUtility.java 测试 HttpUtility.sendPostRequest。该地点标有以下评论：“//这里我需要stackoverflow的帮助”
这已经添加到我在 activity_main.xml 中的按钮中：
android:onClick="sendMessage1"
这是 Mainactivity.java：
package com.example.mythirdapp;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity {
//here I need help from stackoverflow
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
这是HttpUtility.java：
package com.example.mythirdapp;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
public class HttpUtility {
/**
* Represents an HTTP connection
*/
private static HttpURLConnection httpConn;
/**
* Makes an HTTP request using GET method to the specified URL.
*
* @param requestURL
* the URL of the remote server
* @return An HttpURLConnection object
* @throws IOException
* thrown if any I/O error occurred
*/
public static HttpURLConnection sendGetRequest(String requestURL)
throws IOException {
URL url = new URL(requestURL);
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setUseCaches(false);
httpConn.setDoInput(true); // true if we want to read server's response
httpConn.setDoOutput(false); // false indicates this is a GET request
return httpConn;
}
/**
* Makes an HTTP request using POST method to the specified URL.
*
* @param requestURL
* the URL of the remote server
* @param params
* A map containing POST data in form of key-value pairs
* @return An HttpURLConnection object
* @throws IOException
* thrown if any I/O error occurred
*/
public static HttpURLConnection sendPostRequest(String requestURL,
Map<String, String> params) throws IOException {
URL url = new URL(requestURL);
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setUseCaches(false);
httpConn.setDoInput(true); // true indicates the server returns response
StringBuffer requestParams = new StringBuffer();
if (params != null && params.size() > 0) {
httpConn.setDoOutput(true); // true indicates POST request
// creates the params string, encode them using URLEncoder
Iterator<String> paramIterator = params.keySet().iterator();
while (paramIterator.hasNext()) {
String key = paramIterator.next();
String value = params.get(key);
requestParams.append(URLEncoder.encode(key, "UTF-8"));
requestParams.append("=").append(
URLEncoder.encode(value, "UTF-8"));
requestParams.append("&");
}
// sends POST data
OutputStreamWriter writer = new OutputStreamWriter(
httpConn.getOutputStream());
writer.write(requestParams.toString());
writer.flush();
}
return httpConn;
}
/**
* Returns only one line from the server's response. This method should be
* used if the server returns only a single line of String.
*
* @return a String of the server's response
* @throws IOException
* thrown if any I/O error occurred
*/
public static String readSingleLineRespone() throws IOException {
InputStream inputStream = null;
if (httpConn != null) {
inputStream = httpConn.getInputStream();
} else {
throw new IOException("Connection is not established.");
}
BufferedReader reader = new BufferedReader(new InputStreamReader(
inputStream));
String response = reader.readLine();
reader.close();
return response;
}
/**
* Returns an array of lines from the server's response. This method should
* be used if the server returns multiple lines of String.
*
* @return an array of Strings of the server's response
* @throws IOException
* thrown if any I/O error occurred
*/
public static String[] readMultipleLinesRespone() throws IOException {
InputStream inputStream = null;
if (httpConn != null) {
inputStream = httpConn.getInputStream();
} else {
throw new IOException("Connection is not established.");
}
BufferedReader reader = new BufferedReader(new InputStreamReader(
inputStream));
List<String> response = new ArrayList<String>();
String line = "";
while ((line = reader.readLine()) != null) {
response.add(line);
}
reader.close();
return (String[]) response.toArray(new String[0]);
}
/**
* Closes the connection if opened
*/
public static void disconnect() {
if (httpConn != null) {
httpConn.disconnect();
}
}
}
这是 HttpUtilityTester.java：
package com.example.mythirdapp;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
public class HttpUtilityTester {public static void main(String[] args) {
// test sending GET request
String requestURL = "http://www.google.com";
try {
HttpUtility.sendGetRequest(requestURL);
String[] response = HttpUtility.readMultipleLinesRespone();
for (String line : response) {
System.out.println(line);
}
} catch (IOException ex) {
ex.printStackTrace();
}
HttpUtility.disconnect();
System.out.println("=====================================");
// test sending POST request
Map<String, String> params = new HashMap<String, String>();
requestURL = "https://accounts.google.com/ServiceLoginAuth";
params.put("Email", "your_email");
params.put("Passwd", "your_password");
try {
HttpUtility.sendPostRequest(requestURL, params);
String[] response = HttpUtility.readMultipleLinesRespone();
for (String line : response) {
System.out.println(line);
}
} catch (IOException ex) {
ex.printStackTrace();
}
HttpUtility.disconnect();
}
}
我尝试将 HttpUtilityTester.java 的代码添加到我的 Mainactivity.java 中，如下所示：
...public class MainActivity extends Activity {
public void sendMessage1(View v){
// test sending POST request
Map<String, String> params = new HashMap<String, String>();
requestURL = "https://accounts.google.com/ServiceLoginAuth";
params.put("Email", "your_email");
params.put("Passwd", "your_password");
try {
HttpUtility.sendPostRequest(requestURL, params);
String[] response = HttpUtility.readMultipleLinesRespone();
for (String line : response) {
System.out.println(line);
}
} catch (IOException ex) {
ex.printStackTrace();
}
HttpUtility.disconnect();
}...
但是logcat sais：“无法执行活动的方法”