我有一個對話框,它被我的MainActivity調用。在這個對話框裏面有一個自定義按鈕。當我試圖讓該按鈕在我的MainActivity與Android:在對話框中查找按鈕
Button createDateButton = (Button) findViewById(R.id.create_date_button);
是總是空(所以後來我得到一個空指針異常)。我認爲是與對話框中的按鈕有關...
該對話框擴展DialogFragment。它在運行時被稱爲MainActivity內部,作爲對另一個Button的反應。如果您需要了解更多信息,請告訴我
下面是一些代碼:
MainActivity(部分,因爲它有200多個線)
public class MainActivity extends Activity implements UseDateInParentActivityInterface
{
FragmentManager fragmentManager = getFragmentManager();
CreateDialogFragment createDialogFragment;
DialogFragment datePicker;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
homeFragment = new HomeFragment();
fragmentManager.beginTransaction().add(R.id.mainFrame, homeFragment).commit();
findViewById(R.id.bottomButton_home).setBackgroundResource(R.drawable.ic_home);
}
public void openCreate(View view)
{
createDialogFragment = new CreateDialogFragment();
createDialogFragment.show(fragmentManager, "TEST");
updateSelectedButton(3);
}
public void pickDate(View v)
{
datePicker = new DatePickerFragment();
datePicker.show(getFragmentManager(), String.format(getResources().getString(R.string.pickDate)));
}
public void dateForWhatever(int year, int month, int day)
{
DateFormatter dateFormatter = new DateFormatter();
String date = dateFormatter.toStringDE(year, month, day);
Button createDateButton = (Button) findViewById(R.id.create_date_button);
if (createDateButton != null)
{
createDateButton.setText(date);
}
else
{
System.out.println("bloeder Button ist gleich null");
}
}
}
這是DialogFragment的Java類
public class CreateDialogFragment extends DialogFragment
{
@Override
public Dialog onCreateDialog(Bundle savedInstance)
{
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
LayoutInflater layoutInflater = getActivity().getLayoutInflater();
builder.setView(layoutInflater.inflate(R.layout.dialog_create, null))
.setMessage(R.string.create)
.setPositiveButton(R.string.create, new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialogInterface, int i)
{}
})
.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener()
{
@Override
public void onClick(DialogInterface dialogInterface, int i)
{}
});
return builder.create();
}
}
對話框xml.File
<?xml version="1.0" encoding = "utf-8"?>
<RelativeLayout
xmlns:android = "http://schemas.android.com/apk/res/android"
xmlns:tools = "http://schemas.android.com/tools"
android:id = "@+id/dialog_create"
android:layout_width = "match_parent"
android:layout_height = "match_parent"
android:background="@color/create_bg_1"
tools:context = ".CreateDialogFragment"
>
<Button
android:layout_width = "wrap_content"
android:layout_height = "@dimen/textFieldHight"
android:ems = "6"
android:text = "@string/date"
android:background="@color/white"
android:id = "@+id/create_date_button"
android:onClick = "pickDate"
android:layout_below = "@id/dialog_create_name"
/>
</RelativeLayout>
約翰
我更新了我的答案。 – 2014-09-20 20:44:49