Android - DialogFragment - 当触摸EditText时，键盘会在键入之前显示并隐藏

Question

我在DialogFragment上遇到这个问题，带有输入编辑文本框，当弹出对话框并触摸文本框输入时，键盘显示并立即隐藏，向上和向下推动弹出对话框。因此，我无法投入任何东西。

这是对话片段代码

import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import com.test.abc.testingapppay.R;
public class AlertCaptureItemQuantity extends DialogFragment {
   @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        LayoutInflater inflater = getActivity().getLayoutInflater();
        View view = inflater.inflate(R.layout.activity_quantity_prompt,null);
        final EditText quantity = (EditText)            view.findViewById(R.id.text_quantity);
        quantity.requestFocus();

        return new AlertDialog.Builder(getActivity())

                .setView(view)
                .setTitle("Quantity")
                .setCancelable(false)
                .setPositiveButton("Ok", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        // FIRE ZE MISSILES!
                        // val_quantity =Double.parseDouble(quantity.getText().toString());
                        Intent i = new Intent().putExtra("quantityEntered", quantity.getText().toString());
                        getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, i);
                        if (quantity.getText().length() > 0) {
                            dismiss();
                        }
                    }
                })
                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        // User cancelled the dialog
                        dismiss();
                    }
                }).create();
            }
    }

和主要活动的主要呼叫

   AlertCaptureItemQuantity  AlertDialogItems= new AlertCaptureItemQuantity();
   android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();//getFragmentManager();
  AlertDialogItems.show(fragmentManager.beginTransaction(),"items");

对话框的活动xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />
<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="numberDecimal"
    android:ems="10"
    android:id="@+id/text_quantity"
     />
</LinearLayout>

image id dialog