我的手上有一点问题。我的应用程序一直在崩溃，这就是我的堆栈跟踪一直在说的
07-26 10:48:30.582: E/AndroidRuntime(2334): FATAL EXCEPTION: main
07-26 10:48:30.582: E/AndroidRuntime(2334): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.theproblemsolver/com.theproblemsolver.ListView}: android.os.NetworkOnMainThreadException
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.app.ActivityThread.access$600(ActivityThread.java:141)
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.os.Handler.dispatchMessage(Handler.java:99)
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.os.Looper.loop(Looper.java:137)
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-26 10:48:30.582: E/AndroidRuntime(2334): at java.lang.reflect.Method.invokeNative(Native Method)
07-26 10:48:30.582: E/AndroidRuntime(2334): at java.lang.reflect.Method.invoke(Method.java:511)
07-26 10:48:30.582: E/AndroidRuntime(2334): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-26 10:48:30.582: E/AndroidRuntime(2334): at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
07-26 10:48:30.582: E/AndroidRuntime(2334): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
07-26 10:48:30.582: E/AndroidRuntime(2334): at java.net.InetAddress.getAllByName(InetAddress.java:214)
07-26 10:48:30.582: E/AndroidRuntime(2334): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
07-26 10:48:30.582: E/AndroidRuntime(2334): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
07-26 10:48:30.582: E/AndroidRuntime(2334): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
07-26 10:48:30.582: E/AndroidRuntime(2334): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
07-26 10:48:30.582: E/AndroidRuntime(2334): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
07-26 10:48:30.582: E/AndroidRuntime(2334): at com.theproblemsolver.JSONParsser.getJSONFromURI(JSONParsser.java:39)
07-26 10:48:30.582: E/AndroidRuntime(2334): at com.theproblemsolver.ListView.onCreate(ListView.java:34)
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.app.Activity.performCreate(Activity.java:5104)
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
07-26 10:48:30.582: E/AndroidRuntime(2334): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
07-26 10:48:30.582: E/AndroidRuntime(2334): ... 11 more
有人可以告诉我为什么会出现这种错误，我该怎么做才能解决它。这是我的其余代码
public class MainActivity extends Activity {
EditText et;
Button getanswer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button getanswer = (Button) findViewById(R.id.button1);
getanswer.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
new asynctask().execute();
Intent i = new Intent(MainActivity.this, ListView.class);
startActivity(i);
}
//protected void launchNewActivity(){
//startActivity(new Intent(MainActivity.this, ListView.class));
});
}
}
class asynctask extends AsyncTask<String, Void, JSONObject> {
private static final String TAG_RESULTS = "ResultsSet";
private static final String TAG_SUBJECT = "Subject";
private static final String TAG_NUMANSWERS = "NumAnswers";
private static final String TAG_QUESTION = "Question";
private static final String TAG_QUESTION_CONTENT = "Content";
private static final String TAG_QUESTION_CHOSENANSWER = "ChosenAnswer";
private static final String TAG_QUESTION_ANSWERS = "Answers";
public JSONArray json;
@Override
protected JSONObject doInBackground(String... params) {
JSONParsser jParser = new JSONParsser();
String URI = "http://example.com/json";
JSONObject json = jParser.getJSONFromURI(URI);
return json ;
}{ }
@Override
protected void onPostExecute(JSONObject json) {
JSONArray ResultsSet = null ; {
try {
ResultsSet = json.getJSONArray(TAG_RESULTS);
} catch (JSONException e) {
e.printStackTrace();
}
return;
}}
ListView活动
public class ListView extends ListActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.listview);
ArrayList<HashMap<String, String>> questionList = new ArrayList<HashMap<String, String>>();
JSONParsser jParser = new JSONParsser();
String URI = "http://answers.yahooapis.com/AnswerService/V1/questionSearch?appid=4vCW8F3V34GzdMlXOS.yc2WfF5DCnCgqhK0nwCJmEFDgRwEbIgnAoEgJ0zynqOAWtQ&query=sort&type=resolved&results&output=json";;
JSONObject json = jParser.getJSONFromURI(URI);
final String TAG_RESULTS = "ResultsSet";
final String TAG_SUBJECT = "Subject";
final String TAG_NUMANSWERS = "NumAnswers";
final String TAG_QUESTION = "Question";
final String TAG_QUESTION_CONTENT = "Content";
final String TAG_QUESTION_CHOSENANSWER = "ChosenAnswer";
final String TAG_QUESTION_ANSWERS = "Answers";
JSONArray ResultsSet = null;
try {
ResultsSet = json.getJSONArray(TAG_RESULTS);
for(int i = 0; i < ResultsSet.length(); i++){
JSONObject r = ResultsSet.getJSONObject(i);
String Subject = r.getString(TAG_SUBJECT);
String NumAnswers = r.getString(TAG_NUMANSWERS);
JSONObject Question = r.getJSONObject(TAG_QUESTION);
String Content = Question.getString(TAG_QUESTION_CONTENT);
String ChosenAnswer = Question.getString(TAG_QUESTION_CHOSENANSWER);
String Answers = Question.getString(TAG_QUESTION_ANSWERS);
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_SUBJECT, Subject);
map.put(TAG_NUMANSWERS, NumAnswers);
questionList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
ListAdapter adapter = new SimpleAdapter(this, questionList,
R.layout.row,
new String[] { TAG_SUBJECT, TAG_NUMANSWERS }, new int[] {
R.id.Subject, R.id.NumAnswers });
setListAdapter(adapter);
android.widget.ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
String Subject = view.findViewById(R.id.Subject).getContext().toString();
Intent i = new Intent(getApplicationContext(), SingleListItem.class);
i.putExtra(TAG_SUBJECT, Subject);
startActivity(i);
SingleListItem活动
public class SingleListItem extends Activity {
TextView subject;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.singlelistitem);
subject = (TextView) findViewById(R.id.Subject2);
Intent i = getIntent();
String Subject = i.getStringExtra("TAG_SUBJECT");
subject.setText(Subject);
}
}
答案 0 :(得分：0)
看起来你在UI线程中使用网络连接：
String URI = "http://answers.yahooapis.com/AnswerService/V1/questionSearch?appid=4vCW8F3V34GzdMlXOS.yc2WfF5DCnCgqhK0nwCJmEFDgRwEbIgnAoEgJ0zynqOAWtQ&query=sort&type=resolved&results&output=json";;
JSONObject json = jParser.getJSONFromURI(URI);
使用AsyncTask。
答案 1 :(得分：0)
你在第511行的Method.java文件中遇到问题，请看一下。
答案 2 :(得分：0)
您应该以与Main活动类
相同的方式运行此活动 @Override
protected JSONObject doInBackground(String... params) {
JSONParsser jParser = new JSONParsser();
String URI = "http://answers.yahooapis.com/AnswerService/V1/questionSearch?appid=4vCW8F3V34GzdMlXOS.yc2WfF5DCnCgqhK0nwCJmEFDgRwEbIgnAoEgJ0zynqOAWtQ&query=sort&type=resolved&results&output=json";;
JSONObject json = jParser.getJSONFromURI(URI);
return json ;
}
答案 3 :(得分：0)
来自developer.android.com
Potentially long running operations such as network or database operations, or computationally expensive calculations such as resizing bitmaps should be done in a worker thread (or in the case of databases operations, via an asynchronous request).
强制执行以防止Android Not Responding错误。也来自android开发者网站：
In any situation in which your app performs a potentially lengthy operation, you should not perform the work on the UI thread, but instead create a worker thread and do most of the work there. This keeps the UI thread (which drives the user interface event loop) running and prevents the system from concluding that your code has frozen.
http://developer.android.com/training/articles/perf-anr.html http://developer.android.com/reference/android/os/NetworkOnMainThreadException.html
其他人已经为它提供了代码修复。