抱歉我的英语不好..这是我的第一篇文章:D 但是我在 Android/Java 编程方面遇到了一个大问题，而且我在 Android 编程方面真的很新......
我尝试将数据发送到外部 PHP 服务器(在同一网络中)并使用 SharedPreferences 保存。但是，如果我按下“登录”按钮，应用程序总是会崩溃。
这是我的代码: 登录类
public class Login extends ActionBarActivity {
final Context context = this;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
final Button btn_login = (Button) findViewById(R.id.btn_login);
final EditText username = (EditText) findViewById(R.id.login_username);
final EditText password = (EditText) findViewById(R.id.login_password);
final EditText password2 = (EditText) findViewById(R.id.login_password2);
final EditText ip = (EditText) findViewById(R.id.login_ip);
btn_login.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(ip.getText().toString()+"/app/android/login.php");
JSONObject json = new JSONObject();
try {
// JSON data:
json.put("username", username.getText().toString());
json.put("password", password.getText().toString());
JSONArray postjson=new JSONArray();
postjson.put(json);
// Post the data:
httppost.setHeader("json",json.toString());
httppost.getParams().setParameter("jsonpost",postjson);
// Execute HTTP Post Request
System.out.print(json);
@SuppressWarnings("deprecation")
HttpResponse response = httpclient.execute(httppost);
// for JSON:
if(response != null){
InputStream is = response.getEntity().getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "Error!"+e, Toast.LENGTH_LONG).show();
} finally {
try {
is.close();
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "Error!"+e, Toast.LENGTH_LONG).show();
}
}
String text = sb.toString();
if(text == "true"){
//save Username in Preferences
savePreferences("username", username.getText().toString());
//save password in Preferences
savePreferences("password", password.getText().toString());
//save password in Preferences
savePreferences("ip", ip.getText().toString());
Intent i = new Intent(Login.this, Start.class);
startActivity(i);
}
else if(text == "405"){
Toast.makeText(getApplicationContext(), "Error while saving data", Toast.LENGTH_LONG).show();
}
else if(text == "406"){
Toast.makeText(getApplicationContext(), "Passwords aren't the same!", Toast.LENGTH_LONG).show();
}
else if(text == "true408"){
//save Username in Preferences
savePreferences("username", username.getText().toString());
//save password in Preferences
savePreferences("password", password.getText().toString());
//save password in Preferences
savePreferences("ip", ip.getText().toString());
Toast.makeText(getApplicationContext(), "Wieder eingeloggt!", Toast.LENGTH_LONG).show();
Intent i = new Intent(Login.this, Start.class);
startActivity(i);
}
else if(text == "407"){
Toast.makeText(getApplicationContext(), "Passwort falsch!", Toast.LENGTH_LONG).show();
}
else if(text == "404"){
Toast.makeText(getApplicationContext(), "Fehler beim abgleich!", Toast.LENGTH_LONG).show();
}
}
}catch (IOException e) {
Toast.makeText(getApplicationContext(), "Fehler beim Login!"+e, Toast.LENGTH_LONG).show();
} catch (JSONException e1) {
Toast.makeText(getApplicationContext(), "Fehler beim Login!"+e1, Toast.LENGTH_LONG).show();
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.login, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.menu_login_help) {
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
// set title
alertDialogBuilder.setTitle("Hilfe");
// set dialog message
alertDialogBuilder
.setMessage("This is the Tutorial of the App")
.setCancelable(true)
;
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
return true;
}
return super.onOptionsItemSelected(item);
}
private void savePreferences(String key, String value) {
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
Editor editor = sharedPreferences.edit();
editor.putString(key, value);
editor.commit();
}
}
我的 list .xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="de.mbpictures.fastorder"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity android:name=".Main">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".Start" android:label="@string/app_name" ></activity>
<activity android:name=".Login"></activity>
</application>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE" />
</manifest>
最后我的 login.php 在 XAMPP 中运行:
<?php
require("../v0.6/inc/connect.php");
if(isset($_SERVER["HTTP_JSON"])){
$json = $_SERVER['HTTP_JSON'];
$data = json_decode($json);
$username = $data->username;
$password = $data->password;
mysql_select_db("forder_info");
$sql = mysql_query("SELECT * FROM bedienungen WHERE bedienung = '".$username."'");
if(mysql_num_rows($sql) == 0){
if($_POST["pw1"] == $_POST["pw2"]){
$sql_i = "INSERT INTO bedienungen (bedienung, password) VALUES ('".$username."', '".$password."')";
$sql_createTable = "CREATE TABLE IF NOT EXISTS `".$username."` (
`id` int(32) NOT NULL, `essen` text NOT NULL, `tisch` text NOT NULL, `kommentar` text NOT NULL, `bedienung` text NOT NULL, `art` text NOT NULL, `preis` text NOT NULL, `place` text NOT NULL, `time` text NOT NULL) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;";
if(mysql_query($sql_i)){
mysql_select_db("forder_todruck");
if(mysql_query($sql_createTable)){
echo "true";
}
}
else{
?>
405
<?php
}
}
else{
?>
406
<?php
}
}
else{
$sql_c = mysql_query("SELECT * FROM bedienungen WHERE bedienung='".$username."'");
$out_c = mysql_fetch_assoc($sql_c);
if($out_c["password"] == $password){
?>
true408
<?
}
else{
?>
407
<?php
}
}
}
else{
?>404<?php
}
?>
编辑: 现在我将代码编辑为:
public class Login extends ActionBarActivity {
public static final String PREFS_NAME = "Fastorder_Settings";
final Context context = this;
EditText username;
EditText password;
EditText password2;
EditText ip;
ProgressDialog dialog = null;
HttpPost httppost;
StringBuffer buffer;
HttpResponse response;
HttpClient httpclient;
List<NameValuePair> nameValuePairs;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
final Button btn_login = (Button) findViewById(R.id.btn_login);
username = (EditText) findViewById(R.id.login_username);
password = (EditText) findViewById(R.id.login_password);
password2 = (EditText) findViewById(R.id.login_password2);
ip = (EditText) findViewById(R.id.login_ip);
btn_login.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
dialog = ProgressDialog.show(Login.this, "",
"Bitte warten...", true);
new Thread(new Runnable() {
public void run() {
login();
}
}).start();
}
});
}
void login(){
try{
httpclient = new DefaultHttpClient();
httppost = new HttpPost(ip.getText().toString()+"/fastorder/android/login.php"); // make sure the url is correct.
//add your data
nameValuePairs = new ArrayList<NameValuePair>(2);
// Always use the same variable name for posting i.e the android side variable name and php side variable name should be similar,
nameValuePairs.add(new BasicNameValuePair("username", username.getText().toString().trim())); // $Edittext_value = $_POST['Edittext_value'];
nameValuePairs.add(new BasicNameValuePair("password",password.getText().toString().trim()));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
//Execute HTTP Post Request
response=httpclient.execute(httppost);
// edited by James from coderzheaven.. from here....
ResponseHandler<String> responseHandler = new BasicResponseHandler();
final String response = httpclient.execute(httppost, responseHandler);
System.out.println("Response : " + response);
if(response.equalsIgnoreCase("true")){
//save Username in Preferences
savePreferences("username", username.getText().toString());
//save password in Preferences
savePreferences("password", password.getText().toString());
//save password in Preferences
savePreferences("ip", ip.getText().toString());
Intent i = new Intent(Login.this, Start.class);
startActivity(i);
}
else if(response.equalsIgnoreCase("405")){
Toast.makeText(getApplicationContext(), "Fehler beim Speichern", Toast.LENGTH_LONG).show();
}
else if(response.equalsIgnoreCase("406")){
Toast.makeText(getApplicationContext(), "Passwoerte nicht gleich!", Toast.LENGTH_LONG).show();
}
else if(response.equalsIgnoreCase("true408")){
//save Username in Preferences
savePreferences("username", username.getText().toString());
//save password in Preferences
savePreferences("password", password.getText().toString());
//save password in Preferences
savePreferences("ip", ip.getText().toString());
Toast.makeText(getApplicationContext(), "Wieder eingeloggt!", Toast.LENGTH_LONG).show();
Intent i = new Intent(Login.this, Start.class);
startActivity(i);
}
else if(response.equalsIgnoreCase("407")){
Toast.makeText(getApplicationContext(), "Passwort falsch!", Toast.LENGTH_LONG).show();
}
else if(response.equalsIgnoreCase("404")){
Toast.makeText(getApplicationContext(), "Fehler beim abgleich!", Toast.LENGTH_LONG).show();
}
dialog.dismiss();
}catch(Exception e){
dialog.dismiss();
Toast.makeText(getApplicationContext(), "Fehler beim Login!"+e.getMessage(), Toast.LENGTH_LONG).show();
System.out.println("Exception : " + e.getMessage());
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.login, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.menu_login_help) {
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
// set title
alertDialogBuilder.setTitle("Hilfe");
// set dialog message
alertDialogBuilder
.setMessage("Tragen Sie ihre Bedienungsid und Ihr Passwort ein! \n"
+ "Sollten Sie bereits registriert sein, werden sie eingeloggt\n"
+ "andernfalls werden Sie registriert\n \n"
+ "Die Server-IP wird Ihnen vom Admin mitgeteilt.")
.setCancelable(true)
;
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
return true;
}
return super.onOptionsItemSelected(item);
}
private void savePreferences(String key, String value) {
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
Editor editor = sharedPreferences.edit();
editor.putString(key, value);
editor.commit();
}
}
如果我运行 ProgressDialog 会打开一小段时间，然后应用程序再次崩溃......有什么想法......？ 现在我得到这个错误: 目标主机不能为空，也不能在参数中设置。 scheme=null, host=null, path=192.168.178.XX/fastorder/android/login.php
最佳答案
您正在应用程序的主线程上运行与网络相关的代码。解决这个问题的一种方法是启动 AsyncTask然后稍后处理结果，再次回到主线程。
还有其他选择，例如 Handler的，但我相信 AsyncTasks 使与 UI 的交互变得更加简单，我认为这正是您所需要的。
在链接中我passed有一个用于简单文件下载 AsyncTask 的代码 fragment ，其中包含解决此问题所需的一切，请看一下。
关于java - Android 应用程序在访问本地主机时崩溃，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31625474/