顯示java.lang.NullPointerException：爲getDialog（）getWindow（）

Question

我在課堂上收到此錯誤消息

java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window android.app.Dialog.getWindow()' on a null object reference 

我想這

public class ABCD_Fragment extends DialogFragment { 

@Override 
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { 
     getDialog().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE| WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE); 
     super.onViewCreated(view, savedInstanceState); 
    } 

} 

請幫助我。我不明白爲什麼getDialog()是空的。

Answer 1

使用這個，如果你從一個片段調用它：

FragmentManager fragmentManager = getFragmentManager(); 
       ABCD_Fragment mDialogwindow = new ABCD_Fragment(); 
       mDialogwindow.show(fragmentManager, "DIALOG WINDOW"); 

如果從活動稱之爲：

FragmentManager fragmentManager = getSupportFragmentManager(); 
      ABCD_Fragment mDialogwindow = new ABCD_Fragment(); 
mDialogwindow.show(fragmentManager, "DIALOG WINDOW"); 

，然後在ABCD_FRAGMENT補充一點：

getDialog().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE| 
WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE); 
     super.onViewCreated(view, savedInstanceState);