我在我的Android应用程序中进行登录，它正在使用4.4但是在2.3.5它因Log.d("PHP login response", json.toString())而崩溃，如果我把它放在评论中，应用程序将在final String Loginresponse = json.getString("RESPONSE")崩溃。这是我的代码：
protected String doInBackground(String... args) {
final String loginEmail = inputLoginEmail.getText().toString();
final String loginPassword = inputLoginPassword.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("email", loginEmail));
params.add(new BasicNameValuePair("password", loginPassword));
// getting JSON Object
JSONObject json = jsonParser.makeHttpRequest(url_login_user, "POST", params);
// check log cat for PHP response
Log.d("PHP Login Response", json.toString());
// check for success tag
try {
final String Loginresponse = json.getString("RESPONSE");
if(Loginresponse.equals("LOGIN_OK")){ // user successfully logged in
pDialog.dismiss();
//show the user profile
Intent i = new Intent(getApplicationContext(), PubsActivity.class);
i.putExtra("session", loginEmail);
startActivity(i);
// closing this screen
finish();
} else { // failed to login user
pDialog.dismiss();
runOnUiThread(new Runnable(){
@Override
public void run() {
if (Loginresponse.equalsIgnoreCase("LOGIN_MAIL_FORMAT_FAILED")){
Toast.makeText(getApplicationContext(), getString(R.string.invalidEmail), Toast.LENGTH_LONG).show();
} else if (Loginresponse.equalsIgnoreCase("LOGIN_FAILED")) {
Toast.makeText(getApplicationContext(), getString(R.string.wrongLoginData), Toast.LENGTH_LONG).show();
} else if (Loginresponse.equalsIgnoreCase("LOGIN_STATUS_NOK")) {
Toast.makeText(getApplicationContext(), getString(R.string.emailNotConfirmed), Toast.LENGTH_LONG).show();
}
}
});
}
} catch (JSONException e) { //error exception
e.printStackTrace();
}
return null;
}
这是堆栈跟踪：
02-22 14:28:31.570: E/Buffer Error(14816): Error converting result
java.lang.NullPointerException
02-22 14:28:31.570: E/JSON Parser(14816): Error parsing data org.json.JSONException: End of input at character 0 of
02-22 14:28:31.570: W/dalvikvm(14816): threadid=9: thread exiting with uncaught exception (group=0x2aac4560)
02-22 14:28:31.570: E/AndroidRuntime(14816): FATAL EXCEPTION: AsyncTask #1
02-22 14:28:31.570: E/AndroidRuntime(14816): java.lang.RuntimeException: An error occured while executing doInBackground()
02-22 14:28:31.570: E/AndroidRuntime(14816): at android.os.AsyncTask$3.done(AsyncTask.java:200)
02-22 14:28:31.570: E/AndroidRuntime(14816): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
02-22 14:28:31.570: E/AndroidRuntime(14816): at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
02-22 14:28:31.570: E/AndroidRuntime(14816): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
02-22 14:28:31.570: E/AndroidRuntime(14816): at java.util.concurrent.FutureTask.run(FutureTask.java:138)
02-22 14:28:31.570: E/AndroidRuntime(14816): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
02-22 14:28:31.570: E/AndroidRuntime(14816): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
02-22 14:28:31.570: E/AndroidRuntime(14816): at java.lang.Thread.run(Thread.java:1019)
02-22 14:28:31.570: E/AndroidRuntime(14816): Caused by: java.lang.NullPointerException
02-22 14:28:31.570: E/AndroidRuntime(14816): at com.example.kroosky.MainScreenActivity$login.doInBackground(MainScreenActivity.java:181)
02-22 14:28:31.570: E/AndroidRuntime(14816): at com.example.kroosky.MainScreenActivity$login.doInBackground(MainScreenActivity.java:1)
02-22 14:28:31.570: E/AndroidRuntime(14816): at android.os.AsyncTask$2.call(AsyncTask.java:185)
02-22 14:28:31.570: E/AndroidRuntime(14816): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
JSONParser：
package com.example.kroosky;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
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.client.utils.URLEncodedUtils;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.conn.ssl.X509HostnameVerifier;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.SingleClientConnManager;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
import android.util.MalformedJsonException;
import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
Log.d("JASONParser","parse");
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
Log.e("Response: ", String.valueOf(httpEntity));
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
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");
}
Log.e("sb:",sb.toString());
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;
}
}
答案 0 :(得分：1)
您的堆栈跟踪显示您有NullPointerException个例外。您是否验证了JSON响应不为空？尝试捕获NullPointerException异常，应用程序不会崩溃。
答案 1 :(得分：0)
JSONReader是不可用的。据我所知，甚至没有兼容性库。但幸运的是Android是开源的：你需要谷歌搜索它使用的每个文件，复制代码并将文件包含在你的项目中（就像普通的新文件一样）。
您可能需要文件JsonReader.java，JsonScope.java，JsonToken.java，JsonWriter.java，MalformedJsonException.java，StringPool.java。
编辑：第二次阅读你的帖子后，我不太确定你的问题是否存在（不知道你是如何让它在第一时间运行），但随意测试它是否有帮助。我想我记得在它确实有帮助的地方捣乱了。