我对BottomSheetDialog被关闭时的行为非常好奇：当用户向下拖动以隐藏它时，它将保持隐藏状态，即使之后调用bottomSheetDialog#show()也不会显示出来。这种情况只会在向下拖动时发生，而不是用户点击外部区域或程序调用bottomSheetDialog#dismiss()时。
这真的很烦人，因为我有一个里面有RecyclerView的相当大的bottomSheetDialog，每次想要显示bottomSheetDialog时都必须创建一个新的。
因此，与其只是这样做：
if(bottomSheetDialog != null){
bottomSheetDialog.show();
else{
createNewBottomSheetDialog();
}
每次我都必须创建一个新的。
我是漏掉了些什么，还是这是正常行为？（顺便说一句，我使用 appcompat-v7:23.2.1 ）。
我最终通过直接查看BottomSheetDialog的实现来解决了这个问题，发现它只是将一个普通的Dialog包装在一个常规的BottomSheet中。
问题出在BottomSheetCallBack中：
@Override
public void onStateChanged(@NonNull View bottomSheet,
@BottomSheetBehavior.State int newState) {
if (newState == BottomSheetBehavior.STATE_HIDDEN) {
dismiss();
}
}
当对话框被拖动下来以解除时，状态达到了HIDDEN，这时会出现问题。在此之后，即使调用bottomSheetDialog.show()，对话框仍然保持隐藏状态。我找到的最简单的解决方法是删除该状态并将其替换为COLLAPSED状态。
我创建了一个类，复制了整个类，并添加了一行代码来解决该问题：
@Override
public void onStateChanged(@NonNull View bottomSheet,
@BottomSheetBehavior.State int newState) {
if (newState == CustomBottomSheetBehavior.STATE_HIDDEN) {
dismiss();
bottomSheetBehavior.setState(CustomBottomSheetBehavior.STATE_COLLAPSED);
}
}
这里是最终代码：
public class CustomBottomSheetDialog extends AppCompatDialog {
public CustomBottomSheetDialog (@NonNull Context context) {
this(context, 0);
}
public CustomBottomSheetDialog (@NonNull Context context, @StyleRes int theme) {
super(context, getThemeResId(context, theme));
// We hide the title bar for any style configuration. Otherwise, there will be a gap
// above the bottom sheet when it is expanded.
supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
}
protected CustomBottomSheetDialog (@NonNull Context context, boolean cancelable,
OnCancelListener cancelListener) {
super(context, cancelable, cancelListener);
supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
}
@Override
public void setContentView(@LayoutRes int layoutResId) {
super.setContentView(wrapInBottomSheet(layoutResId, null, null));
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setLayout(
ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
}
@Override
public void setContentView(View view) {
super.setContentView(wrapInBottomSheet(0, view, null));
}
@Override
public void setContentView(View view, ViewGroup.LayoutParams params) {
super.setContentView(wrapInBottomSheet(0, view, params));
}
private View wrapInBottomSheet(int layoutResId, View view, ViewGroup.LayoutParams params) {
final CoordinatorLayout coordinator = (CoordinatorLayout) View.inflate(getContext(),
R.layout.design_bottom_sheet_dialog, null);
if (layoutResId != 0 && view == null) {
view = getLayoutInflater().inflate(layoutResId, coordinator, false);
}
FrameLayout bottomSheet = (FrameLayout) coordinator.findViewById(R.id.design_bottom_sheet);
BottomSheetBehavior.from(bottomSheet).setBottomSheetCallback(mBottomSheetCallback);
if (params == null) {
bottomSheet.addView(view);
} else {
bottomSheet.addView(view, params);
}
// We treat the CoordinatorLayout as outside the dialog though it is technically inside
if (shouldWindowCloseOnTouchOutside()) {
coordinator.findViewById(R.id.touch_outside).setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View view) {
if (isShowing()) {
cancel();
}
}
});
}
return coordinator;
}
private boolean shouldWindowCloseOnTouchOutside() {
if (Build.VERSION.SDK_INT < 11) {
return true;
}
TypedValue value = new TypedValue();
//noinspection SimplifiableIfStatement
if (getContext().getTheme()
.resolveAttribute(android.R.attr.windowCloseOnTouchOutside, value, true)) {
return value.data != 0;
}
return false;
}
private static int getThemeResId(Context context, int themeId) {
if (themeId == 0) {
// If the provided theme is 0, then retrieve the dialogTheme from our theme
TypedValue outValue = new TypedValue();
if (context.getTheme().resolveAttribute(
R.attr.bottomSheetDialogTheme, outValue, true)) {
themeId = outValue.resourceId;
} else {
// bottomSheetDialogTheme is not provided; we default to our light theme
themeId = R.style.Theme_Design_Light_BottomSheetDialog;
}
}
return themeId;
}
private BottomSheetBehavior.BottomSheetCallback mBottomSheetCallback
= new BottomSheetBehavior.BottomSheetCallback() {
@Override
public void onStateChanged(@NonNull View bottomSheet,
@BottomSheetBehavior.State int newState) {
if (newState == BottomSheetBehavior.STATE_HIDDEN) {
dismiss();
bottomSheetBehavior.setState(CustomBottomSheetBehavior.STATE_COLLAPSED);
}
}
@Override
public void onSlide(@NonNull View bottomSheet, float slideOffset) {
}
};
}
更新：该问题在某个版本的支持库中得到解决。我并不知道确切的修复版本，但在27.0.2中已经修复了。
注意：由于 Google 对 URL 架构进行了一些修改，因此该 URL 不再指向所描述的问题。
有一个比复制整个类只添加一行更好的解决方法。
// Fix BottomSheetDialog not showing after getting hidden when the user drags it down
myBottomSheetDialog.setOnShowListener(new DialogInterface.OnShowListener() {
@Override
public void onShow(DialogInterface dialogInterface) {
BottomSheetDialog bottomSheetDialog = (BottomSheetDialog) dialogInterface;
FrameLayout bottomSheet = (FrameLayout) bottomSheetDialog
.findViewById(android.support.design.R.id.design_bottom_sheet);
BottomSheetBehavior.from(bottomSheet).setState(BottomSheetBehavior.STATE_COLLAPSED);
}
});
我有一个示例演示，希望它有用。
public class BottomListMenu extends BottomSheetDialog {
private List<MenuDTO> menuList;
private OnMenuItemTapped menuTapListener;
public BottomListMenu(@NonNull Context context, List<MenuDTO> menuList, OnMenuItemTapped menuTapListener) {
super(context);
this.menuList = menuList;
this.menuTapListener = menuTapListener;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dialog_menu_list);
RecyclerView rcvList = (RecyclerView) findViewById(R.id.rcv_menu_list);
rcvList.setLayoutManager(new LinearLayoutManager(getContext()));
BottomSheetMenuListAdapter adapter = new BottomSheetMenuListAdapter(getContext(), this, menuList, menuTapListener);
rcvList.setAdapter(adapter);
}
}
--- 使用 ---
BottomListMenu menu = new BottomListMenu(MainActivity.this, MenuUtils.getListMenu(MainActivity.this), new OnMenuItemTapped() {
@Override
public void onClickMenuItem(MenuDTO menu) {
if (menu.getMenuTitle().equals(getString(R.string.menu_edit))) {
Toast.makeText(MainActivity.this, "Edit Clicked", Toast.LENGTH_SHORT).show();
} else if (menu.getMenuTitle().equals(getString(R.string.menu_delete))) {
Toast.makeText(MainActivity.this, "Delete Clicked", Toast.LENGTH_SHORT).show();
} else if (menu.getMenuTitle().equals(getString(R.string.menu_attach))) {
Toast.makeText(MainActivity.this, "Attach Clicked", Toast.LENGTH_SHORT).show();
}
}
});
menu.show();
-- 完整样例代码在此处提供 --