Question

我正在通过Google的Dialogs上的Android开发者页面，特别是this部分。但是，我没有以编程方式创建DialogFragment的消息，而是使用以下元素创建了一个名为layout_newpayperiod.xml的预设布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<Spinner
    android:id="@+id/spinner_payperiod"
    android:layout_width="fill_parent"
    android:layout_height="48dp"
    android:padding="8dp"
    android:entries="@array/pay_periods"
    />

<EditText
    android:id="@+id/edittext_savepercent"
    android:layout_width="fill_parent"
    android:layout_height="48dp"
    android:padding="8dp"
    android:inputType="number"
    android:hint="Percent to Save"
    />

<EditText
    android:id="@+id/edittext_payment"
    android:layout_width="fill_parent"
    android:layout_height="48dp"
    android:padding="8dp"
    android:inputType="numberDecimal"
    android:hint="Total Payment"
    />

</LinearLayout>

当我调用DialogFragment时，它正常显示，Spinner具有正确的值。我填写了条目并点击“确定”，但是当我尝试从Spinner和两个EditText字段中检索值时，应用程序强制关闭NumberFormatException: Invalid double ""。我觉得我没有正确地检索视图。有人能帮我解决这个问题吗？谢谢！

public class StartPayperiodDialogFragment extends DialogFragment {

/* The activity that creates an instance of this dialog fragment must
 * implement this interface in order to receive event callbacks.
 * Each method passees the DialogFragment in case the host needs to query it.
 */
public interface StartPayperiodDialogListener{
    public void onDialogPositiveClick(DialogFragment dialog);
    public void onDialogNegativeClick(DialogFragment dialog);
}

// Use this instance of the interface to deliver action events
StartPayperiodDialogListener listener;

// Override the Fragment.onAttach() method to instantiate the StartPayperiodDialogListener
@Override
public void onAttach(Activity activity){
    super.onAttach(activity);
    // Verify that the host activity implements the callback interface
    try{
        // Instantiate the NoticeDialogListener so we can send events to the host
        listener = (StartPayperiodDialogListener) activity;
    }catch(ClassCastException e){
        // The activity doesn't implement the interface, throw exception
        throw new ClassCastException(activity.toString() + " must implement StartPayperiodDialogListener");
    }
}

@Override
public Dialog onCreateDialog(Bundle savedInstanceState){
    // Use the Builder class for convenient dialog construction
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    View transactionLayout = View.inflate(getActivity(), R.layout.layout_newpayperiod, null);
    builder.setView(transactionLayout)
    .setPositiveButton("OK", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            // Send the positive button event back to the calling activity
            listener.onDialogPositiveClick(StartPayperiodDialogFragment.this);
        }
    })
    .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            // Send the negative button event back to the calling activity
            listener.onDialogNegativeClick(StartPayperiodDialogFragment.this);
        }
    });
    return builder.create();
}

}

在MainActivity.class中，回调方法：

@Override
public void onDialogPositiveClick(DialogFragment dialog) {
    // User pressed OK, so we need to grab the values from the
    // dialog's fields and apply them to the Views in the Main
    // Activity

    View transactionLayout = View.inflate(this, R.layout.layout_newpayperiod, null);

    // Start with the payment amount
    EditText paymentEt = (EditText) transactionLayout.findViewById(R.id.edittext_payment);
    TextView paymentTv = (TextView) findViewById(R.id.text_paycheck);
    paymentTv.setText(moneyFormat.format(Double.parseDouble(paymentEt.getText().toString())));

    // Next, the percent to save
    EditText savingsEt = (EditText) transactionLayout.findViewById(R.id.edittext_savepercent);
    TextView savingsTv = (TextView) findViewById(R.id.text_savings);
    savingsTv.setText(savingsEt.getText().toString() + "%");

    // Then, the pay period
    Spinner periodSp = (Spinner) transactionLayout.findViewById(R.id.spinner_payperiod);
    TextView periodTv = (TextView) findViewById(R.id.text_payperiod);
    periodTv.setText(periodSp.getSelectedItem().toString());

    // Finally, let's update the daily allowance amount and clear
    // the adapter
    adapter.clear();
    adapter.notifyDataSetChanged();
    TextView allowanceTv = (TextView) findViewById(R.id.text_allowance);
    Double allowanceValue;
    switch(periodSp.getSelectedItemPosition()){
        case(0):    // Daily
            allowanceValue = Double.parseDouble(paymentTv.getText().toString());
            break;
        case(1):    // Weekly
            allowanceValue = Double.parseDouble(paymentTv.getText().toString()) / 7;
            break;
        case(2):    // 2 Weeks
            allowanceValue = Double.parseDouble(paymentTv.getText().toString()) / 14;
            break;
        case(3):    // 30 Days
            allowanceValue = Double.parseDouble(paymentTv.getText().toString()) / 30;
            break;
        default:    // Debugging purposes only
            allowanceValue = 42.0;
            break;
    }
    allowanceTv.setText(Double.toString(allowanceValue));
}

Answer 1

试试这个：

@Override
public void onDialogPositiveClick(DialogFragment dialog) {
    // User pressed OK, so we need to grab the values from the
    // dialog's fields and apply them to the Views in the Main
    // Activity

    // Start with the payment amount
    Dialog dialogView = dialog.getDialog();
    EditText paymentEt = (EditText) dialogView.findViewById(R.id.edittext_payment);

...等（通过以相同的方式查询dialogView，从对话框中检索任何其他视图。）

您的充气代码“膨胀”该视图的全新版本。您想要访问在对话框中创建的那个。

Answer 2

我认为这句话View transactionLayout = View.inflate(this, R.layout.layout_newpayperiod, null);会使一切变得混乱。也许它没有搞乱，但你得到了新创建的布局的地址并将其分配给transactionLayout引用。然后，您将从该布局EditText paymentEt = (EditText) transactionLayout.findViewById(R.id.edittext_payment);获取视图，这些视图当然是未初始化的。它具有值空字符串值 - ＆gt; “”;

我认为您应该使用findViewById来引用EditText，就像使用TextView一样。但是，当您在MainActivity布局可能不是R.layout.layout_newpayperiod的父视图时，您必须找到一种方法来正确地执行此操作。

您在此DialogFragment回调方法中已将onDialogPositiveClick作为参数。所以你可以获得它的View以及你正在寻找的布局 - 它包含你的EditText的

很抱歉很多次编辑这篇文章。

从DialogFragment中的EditText检索值

2 个答案: