记录一下DialogFragment的满屏显示与对话框显示



全屏显示对话框或将其显示为嵌入式片段

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您可能采用以下 UI 设计：您想让一部分 UI 在某些情况下显示为对话框，但在其他情况下全屏显示或显示为嵌入式片段（也许取决于设备使用大屏幕还是小屏幕）。DialogFragment 类便具有这种灵活性，因为它仍然可以充当嵌入式 Fragment。

但在这种情况下，您不能使用 AlertDialog.Builder 或其他 Dialog 对象来构建对话框。如果您想让 DialogFragment 具有嵌入能力，则必须在布局中定义对话框的 UI，然后在 onCreateView() 回调中加载布局。

以下示例 DialogFragment 可以显示为对话框或嵌入式片段（使用名为 purchase_items.xml 的布局）：

public class CustomDialogFragment extends DialogFragment {
    /** The system calls this to get the DialogFragment's layout, regardless
        of whether it's being displayed as a dialog or an embedded fragment. */
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // Inflate the layout to use as dialog or embedded fragment
        return inflater.inflate(R.layout.purchase_items, container, false);
    }
  
    /** The system calls this only when creating the layout in a dialog. */
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // The only reason you might override this method when using onCreateView() is
        // to modify any dialog characteristics. For example, the dialog includes a
        // title by default, but your custom layout might not need it. So here you can
        // remove the dialog title, but you must call the superclass to get the Dialog.
        Dialog dialog = super.onCreateDialog(savedInstanceState);
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
        return dialog;
    }
}

以下代码可根据屏幕尺寸决定将片段显示为对话框还是全屏 UI：

public void showDialog() {
    FragmentManager fragmentManager = getSupportFragmentManager();
    CustomDialogFragment newFragment = new CustomDialogFragment();
    
    if (mIsLargeLayout) {
        // The device is using a large layout, so show the fragment as a dialog
        newFragment.show(fragmentManager, "dialog");
    } else {
        // The device is smaller, so show the fragment fullscreen
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        // For a little polish, specify a transition animation
        transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
        // To make it fullscreen, use the 'content' root view as the container
        // for the fragment, which is always the root view for the activity
        transaction.add(android.R.id.content, newFragment)
                   .addToBackStack(null).commit();
    }
}