Android Http POST 请求不起作用

Question

我有这个安卓代码：

package com.example.webtestconnection;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
private Button login;
private EditText username, password;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
login = (Button) findViewById(R.id.ok);
username = (EditText) findViewById(R.id.name);
password = (EditText) findViewById(R.id.password);
login.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
String   mUsername = username.getText().toString();
String  mPassword = password.getText().toString();
tryLogin(mUsername, mPassword);
}
});
}
protected void tryLogin(String mUsername, String mPassword)
{
HttpURLConnection connection;
OutputStreamWriter request = null;
URL url = null;
String response = null;
String parameters = "username="+mUsername+"&password="+mPassword;
try
{
url = new URL("http://welovelamacompany.altervista.org/test2.php");
connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
connection.setRequestMethod("POST");
request = new OutputStreamWriter(connection.getOutputStream());
request.write(parameters);
request.flush();
request.close();
String line = "";
InputStreamReader isr = new InputStreamReader(connection.getInputStream());
BufferedReader reader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
while ((line = reader.readLine()) != null)
{
sb.append(line + "n");
}
// Response from server after login process will be stored in response variable.
response = sb.toString();
// You can perform UI operations here
Toast.makeText(this,"Message from Server: n"+ response, Toast.LENGTH_LONG).show();
isr.close();
reader.close();
}
catch(IOException e)
{
// Error
}
}
}

这是 php 页面代码：

<?php
//impostazioni server phpmyadmin per poter accedere al db
$servername = "servername";
$username = "username";
$password = "password";
$databasename = "my_databasename";
$Nome_Giocatore = $_POST['username'];
$PasswordGiocatore = $_POST['password'];
try {
$conn = new PDO("mysql:host=$servername;dbname=$databasename", $username, $password);
//imposto una modalità di eccezzione errore
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
//stampo che la connessione è riuscita
$sql=$conn->query("SELECT Password_Giocatore FROM Giocatori WHERE Nome_Giocatore="$Nome_Giocatore"");
$control = $sql->fetch();
$controllo=$control['Password_Giocatore'];
if (password_verify($PasswordGiocatore, $controllo)){
echo "Success";
} else {
echo "Error";
}
$conn->exec($sql);
} catch(PDOException $e){
//stampo che la connessione è fallita e l'errore che ha causato il fallimento
echo "Qualcosa è andato storto :(. Errore: <br/>".$e->getMessage();
}
$conn = null;
?>

但是当我运行它时，它会给我这个错误：

E/Android运行时：致命异常：main 进程： com.example.webtestconnection， PID： 23550 android.os.NetworkOnMainThreadException at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java：1166) at java.net.InetAddress.lookupHostByName(InetAddress.java：385) at java.net.InetAddress.getAllByNameImpl(InetAddress.java：236) at java.net.InetAddress.getAllByName(InetAddress.java：214) at com.android.okhttp.internal.Dns$1.getAllByName(Dns.java：28) at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java：216) at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java：122) at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java：390) at com.android.okhttp.internal.http.HttpEngine.sendSocketRequest(HttpEngine.java：343) at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java：289) at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java：345) at com.android.okhttp.internal.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java：89) at com.android.okhttp.internal.http.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java：197) at com.example.webtestconnection.MainActivity.tryLogin(MainActivity.java：62) at com.example.webtestconnection.MainActivity$1.onClick(MainActivity.java：40) at android.view.view.performClick(View.java：4633) at android.view.View$PerformClick.run(View.java：19270) at android.os.Handler.handleCallback(Handler.java：733) at android.os.Handler.dispatchMessage(Handler.java：95) at android.os.Looper.loop(Looper.java：136) at android.app.ActivityThread.main(ActivityThread.java：5476) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java：515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java：1283) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java：1099) at dalvik.system.NativeStart.main(Native Method)

为什么？我该如何解决它？感谢您的帮助

附言我在清单中拥有互联网权限

Answer 1

请使用 AsyncTask 进行 API 调用，您会收到异常，因为您在 MainThread 上调用它。

class LoginTask extends AsyncTask<String, Void, RSSFeed> {
private Exception exception;
protected YourResponse doInBackground(String... urls) {
try {
URL url = new URL(urls[0]);
//your login code
} catch (Exception e) {
this.exception = e;
} 
}
protected void onPostExecute(YourResponse response) {
// TODO: check this.exception
// TODO: do something with the feed
}
}

并在代码中添加此行

new LoginTask().execute(url);

已编辑您可以在下面为网络调用提供库，更轻松且针对网络调用进行了优化

1. 改造
2. 截击

Answer 2

您正在尝试在主线程上运行 http 连接。这在Android中是绝对禁止的，因为您会破坏应用程序的响应能力。您应该将连接运行到 AsyncTask 中