如何在 Android Studio 中的 PopUp Window 中使用 setText() 方法?

How to use the setText() Method in a PopUp Window In Android Studio?

我的 activity 中有一个 editText 框,用户可以在其中输入 his/her phone 号码,然后单击 Next 按钮。现在,在单击按钮时,我膨胀了一个弹出视图,显示用户 his/her 输入的号码并要求确认。
这里的问题是我无法从 EditText 访问数字以在弹出视图中显示它。谁能告诉我怎么做?

布局充气器:

public void onButtonShowPopupWindowClick(View view) {
    // inflate the layout of the popup window

    LayoutInflater inflater = (LayoutInflater)
            getSystemService(LAYOUT_INFLATER_SERVICE);
    @SuppressLint("InflateParams") View popupView = inflater.inflate(R.layout.confirm_number_popup, null);

    ViewGroup root = (ViewGroup) getWindow().getDecorView().getRootView();
    Button btn1 = popupView.findViewById(R.id.btn_edit);

    // create the popup window
    int width = LinearLayout.LayoutParams.WRAP_CONTENT;
    int height = LinearLayout.LayoutParams.WRAP_CONTENT;

    final PopupWindow popupWindow = new PopupWindow(popupView, width, 
 height, false);

    popupWindow.showAtLocation(view, Gravity.CENTER, 0, 0);
}

当我在充气器中添加这个时,我得到一个空指针异常:

    TextView txt_phone_confirm = 
    findViewById(R.id.txt_phone_number_confirm);
    EditText txt_Phone = findViewById(R.id.Phone_Number);
    txt_phone_confirm.setText(txt_Phone.getText().toString());

这样做,我得到:

 java.lang.NullPointerException: Attempt to invoke virtual method 'void 
 android.widget.TextView.setText(java.lang.CharSequence)' on a null 
 object reference

popupView 上调用按 id 方法查找视图,因为这是具有您的 TextView:

的视图
 TextView txt_phone_confirm = popupView.findViewById(R.id.txt_phone_number_confirm);

这将为您提供刚刚扩充的文本视图。