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我有這個代碼找到網絡周圍，並決定嘗試在我的應用程序，如果它適用。單擊按鈕時，應該在列表視圖中顯示數據庫中的所有數據時顯示活動。Android - 應用程序崩潰時，單擊按鈕以顯示列表視圖的活動
下面的代碼：
MainActivity.java
public class MainActivity extends ListActivity {
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "http://api.androidhive.info/contacts/";
// JSON Node names
private static final String TAG_CONTACTS = "contacts";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_ADDRESS = "address";
private static final String TAG_GENDER = "gender";
private static final String TAG_PHONE = "phone";
private static final String TAG_PHONE_MOBILE = "mobile";
private static final String TAG_PHONE_HOME = "home";
private static final String TAG_PHONE_OFFICE = "office";
// contacts JSONArray
JSONArray contacts = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main5);
contactList = new ArrayList<HashMap<String, String>>();
ListView lv = getListView();
// Listview on item click listener
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String name = ((TextView) view.findViewById(R.id.name))
.getText().toString();
String cost = ((TextView) view.findViewById(R.id.email))
.getText().toString();
String description = ((TextView) view.findViewById(R.id.mobile))
.getText().toString();
// Starting single contact activity
Intent in = new Intent(getApplicationContext(),
SingleContactActivity.class);
in.putExtra(TAG_NAME, name);
in.putExtra(TAG_EMAIL, cost);
in.putExtra(TAG_PHONE_MOBILE, description);
startActivity(in);
}
});
// Calling async task to get json
new GetContacts().execute();
}
/**
* Async task class to get json by making HTTP call
* */
private class GetContacts extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity5.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
contacts = jsonObj.getJSONArray(TAG_CONTACTS);
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
String address = c.getString(TAG_ADDRESS);
String gender = c.getString(TAG_GENDER);
// Phone node is JSON Object
JSONObject phone = c.getJSONObject(TAG_PHONE);
String mobile = phone.getString(TAG_PHONE_MOBILE);
String home = phone.getString(TAG_PHONE_HOME);
String office = phone.getString(TAG_PHONE_OFFICE);
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_ID, id);
contact.put(TAG_NAME, name);
contact.put(TAG_EMAIL, email);
contact.put(TAG_PHONE_MOBILE, mobile);
// adding contact to contact list
contactList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivity5.this, contactList,
R.layout.list_item, new String[] { TAG_NAME, TAG_EMAIL,
TAG_PHONE_MOBILE }, new int[] { R.id.name,
R.id.email, R.id.mobile });
setListAdapter(adapter);
}
}
}
那麼這裏的地方按鈕位於類：
public class MainActivity3Activity extends Activity implements OnClickListener {
Button ViewGradesActivity;
Button ClassScheduleActivity;
Button CalendarOfActivitiesActivity;
Button AccountBalanceActivity;
Button StudentProfileActivity;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_activity3);
ShowMainActivity= (Button) findViewById(R.id.mainactbutton);
ShowMainActivity.setOnClickListener(this);
ClassScheduleActivity = (Button) findViewById(R.id.classSched);
ClassScheduleActivity.setOnClickListener(this);
CalendarOfActivitiesActivity = (Button) findViewById(R.id.activities);
CalendarOfActivitiesActivity.setOnClickListener(this);
AccountBalanceActivity = (Button) findViewById(R.id.balance);
AccountBalanceActivity.setOnClickListener(this);
StudentProfileActivity = (Button) findViewById(R.id.profile);
StudentProfileActivity.setOnClickListener(this);
}
@Override
public void onClick(View view) {
switch(view.getId()) {
//this is to show the activity with the list view
case R.id.mainactbutton:
startActivity(new Intent(this,MainActivity5.class));
break;
case R.id.classSched:
startActivity(new Intent(this,classSchedule.class));
break;
case R.id.activities:
startActivity(new Intent(this,CalendarOfActivities.class));
break;
case R.id.balance:
startActivity(new Intent(this,AccountBalance.class));
break;
case R.id.profile:
startActivity(new Intent(this,StudentProfile.class));
break;
}
}
}
所以每當我單擊mainactbutton應用程序崩潰。我該怎麼辦？列表視圖的活動有什麼問題嗎？
謝謝你的幫助。
編輯：現在，我已經編輯清單文件並添加MainActivity5應用仍然墜毀，這裏的日誌：
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
at android.app.ListActivity.onContentChanged(ListActivity.java:243)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:277)
at android.app.Activity.setContentView(Activity.java:1881)
at com.example.kreshiathea.myfirstapp.MainActivity5.onCreate(MainActivity5.java:52)
at android.app.Activity.performCreate(Activity.java:5122)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1081)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
這裏是我的列表視圖：
activity_main5.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<!-- Main ListView
Always give id value as list(@android:id/list)
-->
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
請張貼logcat的聲明。 – Shadow 2015-03-19 06:18:03
你可以添加logcat嗎？ – mustafasevgi 2015-03-19 06:19:12
錯誤日誌在哪裏？ – Piyush 2015-03-19 06:19:14