我正在尝试创建一个适用于json解析器背景的应用程序，但我不断在每个单一的attmpt上得到错误。我尝试过很多次使用清洁工程，但这并不起作用。
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button startButton = (Button) findViewById(R.id.button);
startButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(MainActivity.this, QuizActivity.class);
startActivity(intent);
}
});
}
这是我的MainActivity.class
package com.fyp.please;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
public class QuizActivity extends ActionBarActivity {
private TextView quizQuestion;
private RadioGroup radioGroup;
private RadioButton optionOne;
private RadioButton optionTwo;
private RadioButton optionThree;
private RadioButton optionFour;
private int currentQuizQuestion;
private int quizCount;
private QuizWrapper firstQuestion;
private List<QuizWrapper> parsedObject;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_quiz);
quizQuestion = (TextView) findViewById(R.id.quiz_question);
radioGroup = (RadioGroup) findViewById(R.id.radioGroup);
optionOne = (RadioButton) findViewById(R.id.radio0);
optionTwo = (RadioButton) findViewById(R.id.radio1);
optionThree = (RadioButton) findViewById(R.id.radio2);
optionFour = (RadioButton) findViewById(R.id.radio3);
Button previousButton = (Button) findViewById(R.id.previousquiz);
Button nextButton = (Button) findViewById(R.id.nextquiz);
AsyncJsonObject asyncObject = new AsyncJsonObject();
asyncObject.execute("");
nextButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int radioSelected = radioGroup.getCheckedRadioButtonId();
int userSelection = getSelectedAnswer(radioSelected);
int correctAnswerForQuestion = firstQuestion.getCorrectAnswer();
if (userSelection == correctAnswerForQuestion) {
// correct answer
Toast.makeText(QuizActivity.this,
"You got the answer correct", Toast.LENGTH_LONG)
.show();
currentQuizQuestion++;
if (currentQuizQuestion >= quizCount) {
Toast.makeText(QuizActivity.this,
"End of the Quiz Questions", Toast.LENGTH_LONG)
.show();
return;
} else {
firstQuestion = parsedObject.get(currentQuizQuestion);
quizQuestion.setText(firstQuestion.getQuestion());
String[] possibleAnswers = firstQuestion.getAnswers()
.split(",");
uncheckedRadioButton();
optionOne.setText(possibleAnswers[0]);
optionTwo.setText(possibleAnswers[1]);
optionThree.setText(possibleAnswers[2]);
optionFour.setText(possibleAnswers[3]);
}
} else {
// failed question
Toast.makeText(QuizActivity.this,
"You chose the wrong answer", Toast.LENGTH_LONG)
.show();
return;
}
}
});
previousButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
currentQuizQuestion--;
if (currentQuizQuestion < 0) {
return;
}
uncheckedRadioButton();
firstQuestion = parsedObject.get(currentQuizQuestion);
quizQuestion.setText(firstQuestion.getQuestion());
String[] possibleAnswers = firstQuestion.getAnswers()
.split(",");
optionOne.setText(possibleAnswers[0]);
optionTwo.setText(possibleAnswers[1]);
optionThree.setText(possibleAnswers[2]);
optionFour.setText(possibleAnswers[3]);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_quiz, 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.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private class AsyncJsonObject extends AsyncTask<String, Void, String> {
private ProgressDialog progressDialog;
@Override
protected String doInBackground(String... params) {
HttpClient httpClient = new DefaultHttpClient(new BasicHttpParams());
HttpPost httpPost = new HttpPost(
"http://192.168.1.5/Android_Quiz/index1.php");
String jsonResult = "";
try {
HttpResponse response = httpClient.execute(httpPost);
jsonResult = inputStreamToString(
response.getEntity().getContent()).toString();
System.out.println("Returned Json object "
+ jsonResult.toString());
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return jsonResult;
}
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog = ProgressDialog.show(QuizActivity.this,
"Downloading Quiz", "Wait....", true);
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
progressDialog.dismiss();
System.out.println("Resulted Value: " + result);
parsedObject = returnParsedJsonObject(result);
if (parsedObject == null) {
return;
}
quizCount = parsedObject.size();
firstQuestion = parsedObject.get(0);
quizQuestion.setText(firstQuestion.getQuestion());
String[] possibleAnswers = firstQuestion.getAnswers().split(",");
optionOne.setText(possibleAnswers[0]);
optionTwo.setText(possibleAnswers[1]);
optionThree.setText(possibleAnswers[2]);
optionFour.setText(possibleAnswers[3]);
}
private StringBuilder inputStreamToString(InputStream is) {
String rLine = "";
StringBuilder answer = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
try {
while ((rLine = br.readLine()) != null) {
answer.append(rLine);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return answer;
}
}
private List<QuizWrapper> returnParsedJsonObject(String result) {
List<QuizWrapper> jsonObject = new ArrayList<QuizWrapper>();
JSONObject resultObject = null;
JSONArray jsonArray = null;
QuizWrapper newItemObject = null;
try {
resultObject = new JSONObject(result);
System.out.println("Testing the water " + resultObject.toString());
jsonArray = resultObject.optJSONArray("quiz_questions");
} catch (JSONException e) {
e.printStackTrace();
}
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonChildNode = null;
try {
jsonChildNode = jsonArray.getJSONObject(i);
int id = jsonChildNode.getInt("id");
String question = jsonChildNode.getString("question");
String answerOptions = jsonChildNode
.getString("possible_answers");
int correctAnswer = jsonChildNode.getInt("correct_answer");
newItemObject = new QuizWrapper(id, question, answerOptions,
correctAnswer);
jsonObject.add(newItemObject);
} catch (JSONException e) {
e.printStackTrace();
}
}
return jsonObject;
}
private int getSelectedAnswer(int radioSelected) {
int answerSelected = 0;
if (radioSelected == R.id.radio0) {
answerSelected = 1;
}
if (radioSelected == R.id.radio1) {
answerSelected = 2;
}
if (radioSelected == R.id.radio2) {
answerSelected = 3;
}
if (radioSelected == R.id.radio3) {
answerSelected = 4;
}
return answerSelected;
}
private void uncheckedRadioButton() {
optionOne.setChecked(false);
optionTwo.setChecked(false);
optionThree.setChecked(false);
optionFour.setChecked(false);
}
}
这是我的测验活动。
04-20 12:44:06.200: W/dalvikvm(924): Unable to resolve superclass of Lcom/fyp/please/QuizActivity; (7)
04-20 12:44:06.200: W/dalvikvm(924): Link of class 'Lcom/fyp/please/QuizActivity;' failed
04-20 12:44:06.210: D/AndroidRuntime(924): Shutting down VM
04-20 12:44:06.250: W/dalvikvm(924): threadid=1: thread exiting with uncaught exception (group=0xb2af4ba8)
04-20 12:44:06.330: E/AndroidRuntime(924): FATAL EXCEPTION: main
04-20 12:44:06.330: E/AndroidRuntime(924): Process: com.fyp.please, PID: 924
04-20 12:44:06.330: E/AndroidRuntime(924): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.fyp.please/com.fyp.please.QuizActivity}: java.lang.ClassNotFoundException: Didn't find class "com.fyp.please.QuizActivity" on path: DexPathList[[zip file "/data/app/com.fyp.please-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.fyp.please-2, /system/lib]]
04-20 12:44:06.330: E/AndroidRuntime(924): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
04-20 12:44:06.330: E/AndroidRuntime(924): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
04-20 12:44:06.330: E/AndroidRuntime(924): at android.app.ActivityThread.access$800(ActivityThread.java:135)
04-20 12:44:06.330: E/AndroidRuntime(924): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
04-20 12:44:06.330: E/AndroidRuntime(924): at android.os.Handler.dispatchMessage(Handler.java:102)
LogCat窗口。
先谢谢
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.fyp.please"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="10"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.fyp.please.QuizActivity"
android:label="@string/title_activity_quiz" >
<intent-filter>
<action android:name="com.fyp.please.QUIZACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
清单： - 这是清单，我在默认活动中没有意图填充它但是它没有工作：（
答案 0 :(得分：0)
要么 -
Intent intent = new Intent(MainActivity.this, QuizActivity.class);
intent.setAction("com.fyp.please.QUIZACTIVITY");
startActivity(intent);
或者
<activity android:name="com.fyp.please.QuizActivity"
android:label="@string/title_activity_quiz" >
</activity>
清洁＆amp;建立项目。从测试设备/ avd卸载以前安装的副本。然后又跑了。
答案 1 :(得分：0)
确保导出源文件夹，Android依赖项和“libs”。
您可以编辑类路径并将exported =“true”添加到值中，或者参见Eclipse：右键＆gt;构建路径..＆gt;配置构建路径，在“订购和导出”选项卡下，您可以设置此值。
然后重建项目。