こんにちは、私はアンドロイドが初めてで、mysql データベースに接続してログイン資格情報をチェックするアプリを開発しています。
これは、エミュレータに表示されるエラーです。
java.lang.NullPointerException
これは私のコードです。
LoginActivity.java
import android.app.Activity;
import java.util.ArrayList;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import android.os.Bundle;
import android.os.StrictMode;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class LoginActivity extends Activity {
EditText un,pw;
TextView error;
Button ok;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
un=(EditText)findViewById(R.id.email_address);
pw=(EditText)findViewById(R.id.password);
ok=(Button)findViewById(R.id.login_button);
error=(TextView)findViewById(R.id.tv_error);
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy =
new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
ok.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();
postParameters.add(new BasicNameValuePair("username", un.getText().toString()));
postParameters.add(new BasicNameValuePair("password", pw.getText().toString()));
//String valid = "1";
String response = null;
try {
response = CustomHttpClient.executeHttpPost("http://engiguide.com/check.php", postParameters); //Enetr Your remote PHP,ASP, Servlet file link
String res=response.toString();
// res = res.trim();
res= res.replaceAll("\\s+","");
//error.setText(res);
if(res.equals("1"))
error.setText("Correct Username or Password");
else
error.setText("Sorry!! Incorrect Username or Password");
} catch (Exception e) {
un.setText(e.toString());
}}
});
}
}
CustomHttpClient.java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.util.ArrayList;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.params.ConnManagerParams;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
public class CustomHttpClient {
/** The time it takes for our client to timeout */
public static final int HTTP_TIMEOUT = 30 * 1000; // milliseconds
/** Single instance of our HttpClient */
private static HttpClient mHttpClient;
/**
* Get our single instance of our HttpClient object.
*
* @return an HttpClient object with connection parameters set
*/
private static HttpClient getHttpClient() {
if (mHttpClient == null) {
mHttpClient = new DefaultHttpClient();
final HttpParams params = mHttpClient.getParams();
HttpConnectionParams.setConnectionTimeout(params, HTTP_TIMEOUT);
HttpConnectionParams.setSoTimeout(params, HTTP_TIMEOUT);
ConnManagerParams.setTimeout(params, HTTP_TIMEOUT);
}
return mHttpClient;
}
/**
* Performs an HTTP Post request to the specified url with the
* specified parameters.
*
* @param url The web address to post the request to
* @param postParameters The parameters to send via the request
* @return The result of the request
* @throws Exception
*/
public static String executeHttpPost(String url, ArrayList postParameters) throws Exception {
BufferedReader in = null;
try {
HttpClient client = getHttpClient();
HttpPost request = new HttpPost(url);
UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(postParameters);
request.setEntity(formEntity);
HttpResponse response = client.execute(request);
in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String line = "";
String NL = System.getProperty("line.separator");
while ((line = in.readLine()) != null) {
sb.append(line + NL);
}
in.close();
String result = sb.toString();
return result;
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}}}}
public static String executeHttpGet(String url) throws Exception {
BufferedReader in = null;
try {
HttpClient client = getHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI(url));
HttpResponse response = client.execute(request);
in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String line = "";
String NL = System.getProperty("line.separator");
while ((line = in.readLine()) != null) {
sb.append(line + NL);
}
in.close();
String result = sb.toString();
return result;
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}}}}}
これは、mysql データベースへの接続に使用される php コードです。
<?php
$un=$_POST['username'];
$pw=$_POST['password'];
//connect to the db
$user = ‘username’;
$pswd = ‘password’;
$db = ‘loginactivity’;
$conn = mysql_connect(‘localhost’, $user, $pswd);
mysql_select_db($db, $conn);
//run the query to search for the username and password the match
$query = “SELECT * FROM userpass WHERE username = ‘$user’ AND password = ‘$pswd’”;
$result = mysql_query($query) or die(“Unable to verify user because : ” . mysql_error());
//this is where the actual verification happens
if(mysql_num_rows($result) > 0)
echo 1; // for correct login response
else
echo 0; // for incorrect login response
?>