NullPointerException异常创建一个新的对话框时， [英] NullPointerException when creating a new Dialog
问题描述
我有一个创建一个列表视图对话框，并在列表项点击我要显示一个警告对话框，但是当我创建对话框它给了我一个 NullPointerException异常与DialogFragment我之前
I have a DialogFragment that creates a listview dialog and on a list item click I want to display an alert dialog but when I create the dialog it gives me a NullPointerException with an error that I have never seen before
08-05 11:40:42.315: E/AndroidRuntime(4693): java.lang.NullPointerException
08-05 11:40:42.315: E/AndroidRuntime(4693): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:142)
08-05 11:40:42.315: E/AndroidRuntime(4693): at android.app.AlertDialog$Builder.<init>(AlertDialog.java:359)
08-05 11:40:42.315: E/AndroidRuntime(4693): at com.tyczj.bowling.dialogs.SeasonType$1$1.onClick(SeasonType.java:60)
08-05 11:40:42.315: E/AndroidRuntime(4693): at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
08-05 11:40:42.315: E/AndroidRuntime(4693): at android.os.Handler.dispatchMessage(Handler.java:99)
08-05 11:40:42.315: E/AndroidRuntime(4693): at android.os.Looper.loop(Looper.java:137)
08-05 11:40:42.315: E/AndroidRuntime(4693): at android.app.ActivityThread.main(ActivityThread.java:4745)
08-05 11:40:42.315: E/AndroidRuntime(4693): at java.lang.reflect.Method.invokeNative(Native Method)
08-05 11:40:42.315: E/AndroidRuntime(4693): at java.lang.reflect.Method.invoke(Method.java:511)
08-05 11:40:42.315: E/AndroidRuntime(4693): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-05 11:40:42.315: E/AndroidRuntime(4693): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-05 11:40:42.315: E/AndroidRuntime(4693): at dalvik.system.NativeStart.main(Native Method)
下面是我的对话框的的onCreate
@Override
public Dialog onCreateDialog(Bundle state){
final Dialog d = new Dialog(getActivity());
d.setContentView(R.layout.dialog_layout);
d.setTitle("Select a season");
ListView lv = (ListView)d.findViewById(R.id.dialog_list);
String[] list = getResources().getStringArray(R.array.season_dialog_type);
lv.setAdapter(new ArrayAdapter<String>(getActivity(),R.layout.stats_list_layout,list));
lv.setOnItemClickListener(new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,long arg3) {
d.dismiss();
FragmentTransaction ft = getFragmentManager().beginTransaction();
if(arg2 == 0){
DialogFragment df = new SeasonsDialog(true);
df.show(ft,null);
}else if(arg2 == 1){
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
final View v = getActivity().getLayoutInflater().inflate(R.layout.add_season_layout, null, false);
builder.setTitle("Add a season").setView(v).setPositiveButton("Add", new OnClickListener(){
@Override
public void onClick(DialogInterface arg0, int arg1) {
arg0.dismiss();
AlertDialog.Builder builder2 = new AlertDialog.Builder(getActivity()); //Error here
builder2.setTitle("Warning!").setMessage("Adding a new season will cause all new games to be under this season.\n\n Do you wish to continue?")
.setPositiveButton("Yes", new OnClickListener(){
@Override
public void onClick(DialogInterface dialog,int which) {
dialog.dismiss();
EditText et = (EditText)v.findViewById(R.id.editText1);
ContentValues values = new ContentValues();
values.put(Games.SEASON, et.getText().toString());
Uri uri = getActivity().getContentResolver().insert(Games.SEASONS_URI, values);
et.setText("");
SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(getActivity());
SharedPreferences.Editor edit = pref.edit();
edit.putLong(Preferences.SELECTED_SEASON, ContentUris.parseId(uri)).commit();
}
}).setNegativeButton("No", new OnClickListener(){
@Override
public void onClick(DialogInterface dialog,int which) {
dialog.dismiss();
}
}).create().show();
}
}).setNegativeButton("Cancel", new OnClickListener(){
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
}).create().show();
}
}
});
return d;
}
它错误的了，在这条线在我的的onClick
AlertDialog.Builder builder2 = new AlertDialog.Builder(getActivity());
这是什么错误是什么意思？
what does that error mean?
推荐答案
这可能是因为你试图调用getActivity（）从内部一个onClick监听器。通常，匿名内部类，如只接入事情是最后。试图创造你的听众做这样的事情之前，权
It could be because you are trying to call getActivity() from within an onClick Listener. Typically Anonymous inner classes like to only access things that are final. Trying right before creating your listener to do something like
final Context context = getActivity();
然后用上下文而不是getActivity（）上的崩溃行了。
and then use context instead of getActivity() on the line that crashes.
和作注。我会用 DialogFragment这里。它管理你的对话框的生命周期要好得多。你会遇到问题，当您尝试旋转画面时的对话框打开。然而，随着DialogFragment很会照顾这对你。
And as a note. I would use DialogFragment here. It manages the lifecycle of your Dialog much better. Your going to run into issues when you try rotating the screen when the Dialog is open. However with the DialogFragment it will take care of this for you.
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