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我有一個Activity，它加載ActionBar中的2個選項卡。標籤1載入Fragment，這將使WebView膨脹，而標籤2使用地圖載入Fragment。最初，我遇到了更改導致應用程序崩潰的選項卡的問題。我遵循指示here並實施onDestroyView()。帶有地圖的片段在按下後退按鈕或方向更改時崩潰應用程序
現在的問題是，如果我按Tab 1（WebView）後退按鈕，它會正確退出Activity。但如果我在選項卡2（地圖）上執行此操作，該應用會崩潰。當我改變方向時，完全相同的情況適用。我確信它與onDestroyView()有關，但我不確定它是什麼。
我甚至試圖Override後退按鈕，但沒有任何作品。
這裏是我的代碼，以提供一些背景：
Activity類：
public class MyActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Displaying the tabs by calling ActionBar
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
//Details Tab
String label1 = getResources().getString(R.string.details);
Tab tab = actionBar.newTab();
tab.setText(label1);
TabListener<DetailsFragment> t1 = new TabListener<DetailsFragment>(this, label1, DetailsFragment.class);
tab.setTabListener(t1);
actionBar.addTab(tab);
//Map Tab
String label2 = getResources().getString(R.string.map);
tab = actionBar.newTab();
tab.setText(label2);
TabListener<MapFragment> t2 = new TabListener<MapFragment>(this, label2, MapFragment.class);
tab.setTabListener(t2);
actionBar.addTab(tab);
}
private class TabListener<T extends Fragment> implements ActionBar.TabListener {
private Fragment mFragment;
private final Activity mActivity;
private final String mTag;
private final Class<T> mClass;
/**
* Constructor used each time a new tab is created.
*
* @param activity
* The host Activity, used to instantiate the fragment
* @param tag
* The identifier tag for the fragment
* @param clz
* The fragment's Class, used to instantiate the fragment
*/
public TabListener(Activity activity, String tag, Class<T> clz) {
mActivity = activity;
mTag = tag;
mClass = clz;
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// Check if the fragment is already initialized
if (mFragment == null) {
// If not, instantiate and add it to the activity
mFragment = Fragment.instantiate(mActivity, mClass.getName());
ft.add(android.R.id.content, mFragment, mTag);
} else {
// If it exists, simply attach it in order to show it
ft.attach(mFragment);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(mFragment);
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// User selected the already selected tab. Usually do nothing.
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
} }
DetailsFragment：
public class DetailsFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.morning, container, false);
WebView webview = (WebView) v.findViewById(R.id.details);
webview.loadUrl("file:///android_asset/pools/details.html");
return v;
} }
MapFragment：
public class MapFragment extends Fragment {
static final LatLng mapLatLng = new LatLng("some numbers", "some numbers");
private GoogleMap map;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.map, container, false);
map = ((MapFragment)getFragmentManager().findFragmentById(R.id.map)).getMap();
Marker amksc = map.addMarker(new MarkerOptions().position(mapLatLng).title("Map"));
map.moveCamera(CameraUpdateFactory.newLatLngZoom(mapLatLng, 18));
return v;
}
@Override
public void onDestroyView() {
super.onDestroyView();
MapFragment destroyMe = (MapFragment)getFragmentManager().findFragmentById(R.id.map);
if (destroyMe != null) {
getFragmentManager().beginTransaction().remove(destroyMe).commit();
}
} }
感謝讀這麼長的帖子。任何幫助是極大的讚賞。我會離開一段時間沒有我的筆記本電腦（準確的15天），所以我可能無法迴應和測試你的答案，但放心，我會=）
在此先感謝！
編輯，包括錯誤日誌（不知道如何格式化）
04-25 11:27:54.333: E/AndroidRuntime(21779): FATAL EXCEPTION: main
04-25 11:27:54.333: E/AndroidRuntime(21779): java.lang.NullPointerException
04-25 11:27:54.333: E/AndroidRuntime(21779): at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1380)
04-25 11:27:54.333: E/AndroidRuntime(21779): at android.app.FragmentManagerImpl$1.run(FragmentManager.java:430)
04-25 11:27:54.333: E/AndroidRuntime(21779): at android.os.Handler.handleCallback(Handler.java:615)
04-25 11:27:54.333: E/AndroidRuntime(21779): at android.os.Handler.dispatchMessage(Handler.java:92)
04-25 11:27:54.333: E/AndroidRuntime(21779): at android.os.Looper.loop(Looper.java:213)
04-25 11:27:54.333: E/AndroidRuntime(21779): at android.app.ActivityThread.main(ActivityThread.java:4786)
04-25 11:27:54.333: E/AndroidRuntime(21779): at java.lang.reflect.Method.invokeNative(Native Method)
04-25 11:27:54.333: E/AndroidRuntime(21779): at java.lang.reflect.Method.invoke(Method.java:511)
04-25 11:27:54.333: E/AndroidRuntime(21779): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
04-25 11:27:54.333: E/AndroidRuntime(21779): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
04-25 11:27:54.333: E/AndroidRuntime(21779): at dalvik.system.NativeStart.main(Native Method)
你也可以發佈錯誤日誌嗎？ – Sharj 2013-04-25 03:22:45
我在問題中添加了LogCat錯誤。謝謝！ – SilverHood 2013-04-25 03:35:26
它看起來並不像完整的錯誤堆棧。你可以像你的代碼一樣格式化它。 – Sharj 2013-04-25 03:38:38