java - 当显示的列表需要滚动时，按钮从 DialogFragment 中消失

Question

AlertDialog 完美地显示内容和按钮，直到内容增长到需要滚动才能显示所有内容的程度。此时按钮消失，即使列表完整显示。

我看到在过去的几年里有人问过这个问题(这个问题与我的基本相同(DialogFragment buttons pushed off screen API 24 and above)，但答案似乎都是命中注定的，甚至是随意的:设置 layout_weight，从 setMessage() 切换到 setTitle()，最后从 AlertDialog 切换到 Dialog。

这些都不适用于我，避免 AlertDialog 不是一个吸引人的选项，因为我使用的 setMultiChoiceItems() 方法似乎(对我来说令人难以置信，也许考虑到我的知识极其有限)仅适用于 AlertDialog。

因此，在绝望和沮丧中，我直接求助于 stackoverflow 的集体大脑。

这是我的 DialogFragment 的精简版:

public class SurfaceDialog extends DialogFragment {
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        LayoutInflater inflater = requireActivity().getLayoutInflater();
        builder.setView(inflater.inflate(R.layout.surface_dialog, null))
                .setTitle(mMessage)
                .setMultiChoiceItems(mSurfaceList, mCheckedSurfaces, new DialogInterface.OnMultiChoiceClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                        if (isChecked) {
                            mCheckedSurfacesPositions.add(which);
                        } else {
                            mCheckedSurfacesPositions.remove(mCheckedSurfacesPositions.indexOf(which));
                        }
                    }
                });

        // builder.setCancelable(false);
        builder.setPositiveButton("Done", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                ProcessDialogSelections(mCheckedSurfacesPositions);
                dismiss();
            }

        }).setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                listener.onSurfaceDialogSelectedSent(mUnitSurfaces);
                dismiss();
            }
        });

        return builder.create();
    }

那不起作用，然后我编写了自己的按钮并显示它们:

    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        LayoutInflater inflater = requireActivity().getLayoutInflater();
        View dialogView = inflater.inflate(R.layout.surface_dialog, null);
        builder.setView(dialogView)
                .setTitle(mMessage)

                .setMultiChoiceItems(mSurfaceList, mCheckedSurfaces, new DialogInterface.OnMultiChoiceClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                        if (isChecked) {
                            mCheckedSurfacesPositions.add(which);
                        } else {
                            mCheckedSurfacesPositions.remove(mCheckedSurfacesPositions.indexOf(which));
                        }
                    }
                });

        Button positiveButton = dialogView.findViewById(R.id.positive_button);
        Button negativeButton = dialogView.findViewById(R.id.negative_button);

        positiveButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ProcessDialogSelections(mCheckedSurfacesPositions);
                dismiss();
            }
        });
        negativeButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                listener.onSurfaceDialogSelectedSent(mUnitSurfaces);
                dismiss();
            }
        });

        return builder.create();

    }

这是我修改后的 XML 文件

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout android:layout_height="match_parent"
    android:layout_width="match_parent"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        android:orientation="vertical">

    </ScrollView>


    <Button
        android:id="@+id/positive_button"
        android:layout_height="wrap_content"
        android:layout_marginBottom="30dp"
        android:layout_width="wrap_content"
        android:text="Done"
        app:layout_constraintBaseline_toBaselineOf="@+id/negative_button"
        app:layout_constraintEnd_toStartOf="@+id/negative_button"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:id="@+id/negative_button"
        android:layout_height="wrap_content"
        android:layout_marginBottom="30dp"
        android:layout_width="wrap_content"
        android:text="Cancel"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/positive_button" />

</androidx.constraintlayout.widget.ConstraintLayout>

由于那不起作用，然后我听从了 Vikas Singh ( AlertDialog Buttons not visible when using Custom layout) 的建议。这就是新代码的样子(本质上是用 Java 而不是 XML 创建布局。

    public Dialog onCreateDialog(Bundle savedInstanceState) {

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

        // New code from Vikas Singh
        LinearLayout rootLayout = new LinearLayout(getActivity());
        rootLayout.setOrientation(LinearLayout.VERTICAL);
        ScrollView scrollView = new ScrollView(getActivity());
        LinearLayout layout = new LinearLayout(getActivity());
        layout.setOrientation(LinearLayout.VERTICAL);

        scrollView.addView(layout);
        rootLayout.addView(scrollView);
        builder.setNegativeButton("Cancel", null);
        builder.setPositiveButton("Go", null);
        builder.setView(rootLayout);

        builder//.setView(dialogView)
                //.setTitle(mMessage)

                .setMultiChoiceItems(mSurfaceList, mCheckedSurfaces, new DialogInterface.OnMultiChoiceClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                        if (isChecked) {
                            mCheckedSurfacesPositions.add(which);
                        } else {
                            mCheckedSurfacesPositions.remove(mCheckedSurfacesPositions.indexOf(which));
                        }
                    }
                });
        return builder.create();
    }

当我必须滚动时仍然没有按钮。
为什么不呢，我能做些什么呢？

Answer 1

这是解决方案:

public class SurfaceDialog extends DialogFragment {
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        //LayoutInflater inflater = requireActivity().getLayoutInflater();
        builder
               //.setView(inflater.inflate(R.layout.surface_dialog, null)) didn't work
               // nor did setView with android.R.layout.select_dialog_multichoice
               // nor android.R.layout.simple_list_item_multiple_choice work
                .setTitle(mMessage)
                .setMultiChoiceItems(mSurfaceList, mCheckedSurfaces, new DialogInterface.OnMultiChoiceClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                        if (isChecked) {
                            mCheckedSurfacesPositions.add(which);
                        } else {
                            mCheckedSurfacesPositions.remove(mCheckedSurfacesPositions.indexOf(which));
                        }
                    }
                });

        // builder.setCancelable(false);
        builder.setPositiveButton("Done", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                ProcessDialogSelections(mCheckedSurfacesPositions);
                dismiss();
            }

        }).setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                listener.onSurfaceDialogSelectedSent(mUnitSurfaces);
                dismiss();
            }
        });

        return builder.create();
    }

multiChoiceItems DialogFragment 现在就像一个魅力!
我所要做的就是简单地注释掉上面的行。
结果，没有显式膨胀的布局，没有 View 集。
但它仍然有效。

现在，如果有人可以向我解释，我会很高兴的

为什么这个工作的细节，

为什么另一个没有，

鉴于较早的失败，如何实现自定义布局以实现 View 滚动时不丢失操作按钮的结果