我在android中遇到json的问题 我目前有来自2个类的以下代码，这些类是JSONParser.java dan Tab1.java用于登录功能。 这将在android 2.3.3及更低版本中像魅力一样工作，但如果在它之上它就不起作用。 （蜂窝，ICS，JB） 我在谷歌搜索这个问题，我发现它与asynctask有关，但我仍然不明白如何在我的代码中实现它。 很抱歉问新手问题，感谢您的帮助 谢谢。
JSONParser.java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject AmbilJson(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, "iso-8859-1"), 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;
}
}
这是登录类
Tab1.java
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Tab1 extends Activity {
String var_usr,var_pass;
EditText usr, psw;
JSONArray str_login = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.panel_login);
usr = (EditText) findViewById(R.id.txt_username);
psw = (EditText) findViewById(R.id.txt_pass);
Button submit = (Button) findViewById(R.id.btn_login);
submit.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
var_usr = usr.getText().toString();
var_pass = psw.getText().toString();
String stts = "";
String kode = "";
String link_url = "http://10.0.2.2/gollege/login.php?usr="+var_usr+"&psw="+var_pass;
com.bucheuw.gollege.portal.JSONParser jParser = new com.bucheuw.gollege.portal.JSONParser();
JSONObject json = jParser.AmbilJson(link_url);
try {
str_login = json.getJSONArray("statuslogin");
for(int i = 0; i < str_login.length(); i++){
JSONObject ar = str_login.getJSONObject(i);
TextView st = (TextView) findViewById(R.id.txt_alert);
String alrt = ar.getString("hasil");
stts = ar.getString("st");
kode = ar.getString("id");
st.setText(alrt);
usr.setText("");
psw.setText("");
if(stts.trim().equals("ok"))
{
Intent ni = null;
ni = new Intent(Tab1.this, com.bucheuw.gollege.portal.DashboardActivity.class);
Bundle b = new Bundle();
b.putString("par_kode", kode);
ni.putExtras(b);
startActivity(ni);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
});
}
}
logcat错误行
01-21 18:25:57.016: E/AndroidRuntime(533): FATAL EXCEPTION: main
01-21 18:25:57.016: E/AndroidRuntime(533): android.os.NetworkOnMainThreadException
01-21 18:25:57.016: E/AndroidRuntime(533): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
01-21 18:25:57.016: E/AndroidRuntime(533): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
01-21 18:25:57.016: E/AndroidRuntime(533): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
01-21 18:25:57.016: E/AndroidRuntime(533): at libcore.io.IoBridge.connect(IoBridge.java:112)
01-21 18:25:57.016: E/AndroidRuntime(533): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
01-21 18:25:57.016: E/AndroidRuntime(533): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
01-21 18:25:57.016: E/AndroidRuntime(533): at java.net.Socket.connect(Socket.java:842)
01-21 18:25:57.016: E/AndroidRuntime(533): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
01-21 18:25:57.016: E/AndroidRuntime(533): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
01-21 18:25:57.016: E/AndroidRuntime(533): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
01-21 18:25:57.016: E/AndroidRuntime(533): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
01-21 18:25:57.016: E/AndroidRuntime(533): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
01-21 18:25:57.016: E/AndroidRuntime(533): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
01-21 18:25:57.016: E/AndroidRuntime(533): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
01-21 18:25:57.016: E/AndroidRuntime(533): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
01-21 18:25:57.016: E/AndroidRuntime(533): at com.bucheuw.gollege.portal.JSONParser.AmbilJson(JSONParser.java:38)
01-21 18:25:57.016: E/AndroidRuntime(533): at com.bucheuw.gollege.Tab1$1.onClick(Tab1.java:51)
01-21 18:25:57.016: E/AndroidRuntime(533): at android.view.View.performClick(View.java:3511)
01-21 18:25:57.016: E/AndroidRuntime(533): at android.view.View$PerformClick.run(View.java:14105)
01-21 18:25:57.016: E/AndroidRuntime(533): at android.os.Handler.handleCallback(Handler.java:605)
01-21 18:25:57.016: E/AndroidRuntime(533): at android.os.Handler.dispatchMessage(Handler.java:92)
01-21 18:25:57.016: E/AndroidRuntime(533): at android.os.Looper.loop(Looper.java:137)
01-21 18:25:57.016: E/AndroidRuntime(533): at android.app.ActivityThread.main(ActivityThread.java:4424)
01-21 18:25:57.016: E/AndroidRuntime(533): at java.lang.reflect.Method.invokeNative(Native Method)
01-21 18:25:57.016: E/AndroidRuntime(533): at java.lang.reflect.Method.invoke(Method.java:511)
01-21 18:25:57.016: E/AndroidRuntime(533): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-21 18:25:57.016: E/AndroidRuntime(533): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-21 18:25:57.016: E/AndroidRuntime(533): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：2)
那是因为在以后的版本中你不能在主线程中进行网络连接。
使用AsyncTask ..
私有类MyTask扩展了AsyncTask {
private Context context;
public MyTask(Context context) {
this.context = context;
}
protected void onPreExecute() {
progressDialog = ProgressDialog.show(context, "", "msg", true);
}
protected Long doInBackground(URL... urls) {
//add here your json part
}
protected void onPostExecute(Long result) {
progressDialog.dismiss();
Intent ni = null;
ni = new Intent(Tab1.this, com.bucheuw.gollege.portal.DashboardActivity.class);
Bundle b = new Bundle();
b.putString("par_kode", kode);
ni.putExtras(b);
startActivity(ni);
}
}
答案 1 :(得分：0)
您可能遇到的问题是NetworkOnMainThreadException。
从ICS及以上版本中，Android将不允许在UI线程中进行任何网络操作。它应该在单独的线程中完成，因此它不会挂起UI。在单独的线程中尝试您的网络通信代码。