对不起，我的英文。我无法以任何方式显示从json链接获取的数据。就像互联网上的很多例子一样，但我似乎无法理解错误是什么。我认为这是不正确的PHP文件，虽然它可以。我问你，程序员有助于理解为什么应用程序不起作用。下面我把所有的文件： 从中我想读数据http://ksupulse.tk/get_all.php从url中阅读json（Android）
db_config.php
<?php
define('DB_USER', "login");
define('DB_PASSWORD', "pass");
define('DB_DATABASE', "database");
define('DB_SERVER', "server");
?>
db_connect.php
<?php
/**
* A class file to connect to database
*/
class DB_CONNECT {
// constructor
function __construct() {
// connecting to database
$this->connect();
}
// destructor
function __destruct() {
// closing db connection
$this->close();
}
/**
* Function to connect with database
*/
function connect() {
// import database connection variables
require_once __DIR__ . '/db_config.php';
// Connecting to mysql database
$con = mysql_connect(DB_SERVER, DB_USER, DB_PASSWORD) or die(mysql_error());
// Selecing database
$db = mysql_select_db(DB_DATABASE) or die(mysql_error()) or die(mysql_error());
// returing connection cursor
return $con;
}
/**
* Function to close db connection
*/
function close() {
// closing db connection
mysql_close();
}
}
?>
工作JSON链接get_all.php
<?php
header('Content-Type: application/json; charset=utf-8');
$response = array();
require 'db_connect.php';
$db = new DB_CONNECT();
$result = mysql_query("SELECT * FROM demo") or die(mysql_error());
if (mysql_num_rows($result) > 0) {
$response["demo"] = array();
while ($row = mysql_fetch_array($result)) {
$product = array();
$product["id"] = $row["id"];
$product["name"] = $row["name"];
$product["detaly"] = $row["detaly"];
array_push($response["demo"], $product);
}
$response["success"] = 1;
echo json_encode($response);
} else {
$response["success"] = 0;
$response["message"] = "No products found";
echo json_encode($response);
}
?>
Android的文件：
MainActivity
public class MainActivity extends Activity {
//URL to get JSON Array
private static String url = "http://ksupulse.tk/get_all.php";
//JSON Node Names
private static final String TAG_USER = "detaly";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
JSONArray user = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Creating new JSON Parser
JSONParser jParser = new JSONParser();
// Getting JSON from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting JSON Array
user = json.getJSONArray(TAG_USER);
JSONObject c = user.getJSONObject(0);
// Storing JSON item in a Variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
//Importing TextView
final TextView uid = (TextView)findViewById(R.id.uid);
final TextView name1 = (TextView)findViewById(R.id.name);
final TextView email1 = (TextView)findViewById(R.id.email);
//Set JSON Data in TextView
uid.setText(id);
name1.setText(name);
email1.setText(email);
} catch (JSONException e) {
e.printStackTrace();
}
}
JSONParser
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "utf-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
这是我的错误我关注的东西：
11-22 18:37:57.448: E/JSON Parser(1850): Error parsing data org.json.JSONException: Value of type java.lang.String cannot be converted to JSONObject
所有错误：
11-22 18:37:54.748: E/Trace(1850): error opening trace file: No such file or directory (2) 11-22 18:37:57.448: E/JSON Parser(1850): Error parsing data org.json.JSONException: Value of type java.lang.String cannot be converted to JSONObject 11-22 18:37:57.448: D/AndroidRuntime(1850): Shutting down VM 11-22 18:37:57.460: W/dalvikvm(1850): threadid=1: thread exiting with uncaught exception (group=0xa6265288) 11-22 18:37:57.468: E/AndroidRuntime(1850): FATAL EXCEPTION: main 11-22 18:37:57.468: E/AndroidRuntime(1850): java.lang.RuntimeException: Unable to start activity ComponentInfo{learn2crack.jsonparsing/learn2crack.jsonparsing.MainActivity}: java.lang.NullPointerException 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.app.ActivityThread.access$600(ActivityThread.java:130) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.os.Handler.dispatchMessage(Handler.java:99) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.os.Looper.loop(Looper.java:137) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.app.ActivityThread.main(ActivityThread.java:4745) 11-22 18:37:57.468: E/AndroidRuntime(1850): at java.lang.reflect.Method.invokeNative(Native Method) 11-22 18:37:57.468: E/AndroidRuntime(1850): at java.lang.reflect.Method.invoke(Method.java:511) 11-22 18:37:57.468: E/AndroidRuntime(1850): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 11-22 18:37:57.468: E/AndroidRuntime(1850): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 11-22 18:37:57.468: E/AndroidRuntime(1850): at dalvik.system.NativeStart.main(Native Method) 11-22 18:37:57.468: E/AndroidRuntime(1850): Caused by: java.lang.NullPointerException 11-22 18:37:57.468: E/AndroidRuntime(1850): at learn2crack.jsonparsing.MainActivity.onCreate(MainActivity.java:43) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.app.Activity.performCreate(Activity.java:5008) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 11-22 18:37:57.468: E/AndroidRuntime(1850): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 11-22 18:37:57.468: E/AndroidRuntime(1850): ... 11 more 11-22 18:57:04.626: E/JSON Parser(1888): Error parsing data org.json.JSONException: Value of type java.lang.String cannot be converted to JSONObject 11-22 18:57:04.626: D/AndroidRuntime(1888): Shutting down VM 11-22 18:57:04.626: W/dalvikvm(1888): threadid=1: thread exiting with uncaught exception (group=0xa6265288) 11-22 18:57:04.626: E/AndroidRuntime(1888): FATAL EXCEPTION: main 11-22 18:57:04.626: E/AndroidRuntime(1888): java.lang.RuntimeException: Unable to start activity ComponentInfo{learn2crack.jsonparsing/learn2crack.jsonparsing.MainActivity}: java.lang.NullPointerException 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.app.ActivityThread.access$600(ActivityThread.java:130) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.os.Handler.dispatchMessage(Handler.java:99) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.os.Looper.loop(Looper.java:137) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.app.ActivityThread.main(ActivityThread.java:4745) 11-22 18:57:04.626: E/AndroidRuntime(1888): at java.lang.reflect.Method.invokeNative(Native Method) 11-22 18:57:04.626: E/AndroidRuntime(1888): at java.lang.reflect.Method.invoke(Method.java:511) 11-22 18:57:04.626: E/AndroidRuntime(1888): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 11-22 18:57:04.626: E/AndroidRuntime(1888): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 11-22 18:57:04.626: E/AndroidRuntime(1888): at dalvik.system.NativeStart.main(Native Method) 11-22 18:57:04.626: E/AndroidRuntime(1888): Caused by: java.lang.NullPointerException 11-22 18:57:04.626: E/AndroidRuntime(1888): at learn2crack.jsonparsing.MainActivity.onCreate(MainActivity.java:43) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.app.Activity.performCreate(Activity.java:5008) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 11-22 18:57:04.626: E/AndroidRuntime(1888): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 11-22 18:57:04.626: E/AndroidRuntime(1888): ... 11 more