我已经潜伏了这个网站很长一段时间了，幸运的是直到现在我所有的问题都得到了解答。我希望你们中的一些人可以在这里阐明我的问题。我可以成功地获取ListView以显示字符串数组 - 但是当我尝试将JSON数据解析为数组时 - 我的程序只是强制关闭而LogCat对我没什么帮助。 Anywho - 这是我正在使用的代码。

String[] journals = {"Filler"};

String result;

JSONArray jArray[];

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

try{

//http post

HttpClient httpclient = new DefaultHttpClient();

HttpPost httppost = new HttpPost("http://xxx.xxx.xxx.xxx/query.php");

org.apache.http.HttpResponse response = httpclient.execute(httppost);

HttpEntity entity = response.getEntity();

InputStream is = entity.getContent();

//convert response to string

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();

result=sb.toString();

//I think the problem is somewhere here ....

JSONArray jArray = new JSONArray(result);

for(int i=0;i

JSONObject json_data = jArray.getJSONObject(i);

journals[i] = json_data.getString("JournalName");

Log.i("log_tag","JournalID: "+json_data.getInt("JournalID") +

",JournalName: " + json_data.getString("JournalName"));

}

}

catch (Exception e) {

}

//Or here -- I know this code should REALLY be separated and not in onCreate -- I feel like that's half my problem

setListAdapter(new ArrayAdapter(this, R.layout.list_item, journals));

ListView lv = getListView();

先谢谢你们！我很感激。

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): FATAL EXCEPTION: main

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): java.lang.RuntimeException: Unable to start activity ComponentInfo{Andrew.Badura.A4A.com/Andrew.Badura.A4A.com.SurvAcademia}: java.lang.RuntimeException: Unable to start activity ComponentInfo{Andrew.Badura.A4A.com/Andrew.Badura.A4A.com.JournalActivity}: java.lang.NullPointerException

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread.access$2300(ActivityThread.java:125)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.os.Handler.dispatchMessage(Handler.java:99)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.os.Looper.loop(Looper.java:123)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread.main(ActivityThread.java:4627)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at java.lang.reflect.Method.invokeNative(Native Method)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at java.lang.reflect.Method.invoke(Method.java:521)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at dalvik.system.NativeStart.main(Native Method)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): Caused by: java.lang.RuntimeException: Unable to start activity ComponentInfo{Andrew.Badura.A4A.com/Andrew.Badura.A4A.com.JournalActivity}: java.lang.NullPointerException

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread.startActivityNow(ActivityThread.java:2503)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:127)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:339)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:654)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.widget.TabHost.setCurrentTab(TabHost.java:326)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.widget.TabHost.addTab(TabHost.java:216)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at Andrew.Badura.A4A.com.SurvAcademia.onCreate(SurvAcademia.java:25)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): ... 11 more

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): Caused by: java.lang.NullPointerException

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at java.util.Arrays$ArrayList.(Arrays.java:49)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at java.util.Arrays.asList(Arrays.java:171)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.widget.ArrayAdapter.(ArrayAdapter.java:125)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at Andrew.Badura.A4A.com.JournalActivity.onCreate(JournalActivity.java:69)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)

03-07 22:24:33.060: ERROR/AndroidRuntime(7986): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)