转载请标明出处：http://blog.csdn.net/zhaoyanjun6/article/details/127967304
本文出自【赵彦军的博客】

文章目录

• 效果
• BottomSheet
• BottomSheetDialog
• BottomSheetDialogFragment
• 圆角效果
• 去掉背景蒙版
• 设置蒙版透明度
• 点击 dialog 外部区域，dialog 不消失
• 禁止向下拖动
• 设置弹框固定高度
• 内容铺满全屏
• 监听展开收起
• 底部常驻View

效果

MD风格的底部弹窗，比自定义dialog或popupwindow使用更简单，功能也更强大。

其实细分来说，是BottomSheet、BottomSheetDialog、BottomSheetDialogFragment

代码 https://gitee.com/zhaoyanjun/bottomSheetDialogFragmentDemo

BottomSheet

与主界面同层级关系，可以事件触发，如果有设置显示高度的话，也可以拉出来，且不会影响主界面的交互。

XML

注意，

• 这里需要协调布局CoordinatorLayout包裹才行
• app:behavior_peekHeight 显示高度，不显示的话设置为0即可
• app:layout_behavior 标示这是一个bottom_sheet

以上3个条件都是必须的。

代码

 View bottomView = findViewById(R.id.ll_bottom_sheet);bottomView.setOnClickListener(v -> {BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomView);if (behavior.getState() == BottomSheetBehavior.STATE_EXPANDED) {//如果是展开状态，则关闭，反之亦然behavior.setState(BottomSheetBehavior.STATE_COLLAPSED);} else {behavior.setState(BottomSheetBehavior.STATE_EXPANDED);}});

• STATE_COLLAPSED： 折叠状态
• STATE_EXPANDED： 展开状态
• STATE_DRAGGING ： 过渡状态
• STATE_SETTLING： 视图从脱离手指自由滑动到最终停下的这一小段时间
• STATE_HIDDEN ： 默认无此状态（可通过app:behavior_hideable 启用此状态），启用后用户将能通过向下滑动完全隐藏 bottom sheet

BottomSheetDialog

可以看到弹出来之后是有一个半透明的蒙层的，这时候是影响主界面交互的，也就意味着此时BottomSheetDialog的优先级是要高于主界面的。

代码

public class MyBottomSheetDialog extends BottomSheetDialog {public MyBottomSheetDialog(@NonNull Context context) {super(context);}public MyBottomSheetDialog(@NonNull Context context, int theme) {super(context, theme);}protected MyBottomSheetDialog(@NonNull Context context, boolean cancelable, OnCancelListener cancelListener) {super(context, cancelable, cancelListener);}
}    

显示 Dialog

MyBottomSheetDialog bottomSheetDialog = new MyBottomSheetDialog(this);
bottomSheetDialog.setContentView(R.layout.bottom_dialog_layout);
bottomSheetDialog.show();

bottom_dialog_layout :

比较简单的使用方式，直接实例化之后setContentView，然后调用show就可以了。
这里只是一个展示效果，实际上使用场景可能会复杂一些，还要做一些操作等等，所以，也可以自定义dialog继承自BottomSheetDialog，然后处理自己的业务逻辑。

BottomSheetDialogFragment

效果跟BottomSheetDialog差不多，代码跟DialogFragment差不多。

代码

public class MyDialogFragment extends BottomSheetDialogFragment {@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {View view = inflater.inflate(R.layout.bottom_dialog_fragment_layout, container, false);return view;}
}

bottom_dialog_fragment_layout

显示

MyDialogFragment dialog = new MyDialogFragment();
Bundle bundle = new Bundle();
dialog.setArguments(bundle);
dialog.show(getSupportFragmentManager(), "dialog_fragment");

但是在实际开发中，我们的需求可能并不能满足于此，比如上部分圆角效果、指定高度等

圆角效果

先设置原有背景透明

style.xml

onCreate中设置style

public class MyDialogFragment extends BottomSheetDialogFragment {@Overridepublic void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setStyle(STYLE_NORMAL, R.style.MyBottomSheetDialog);}@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {View view = inflater.inflate(R.layout.bottom_dialog_fragment_layout, container, false);return view;}
}

在根布局的 view上设置 background

特别注意：根布局除了设置 android:background 属性外，还需要设置 android:padding 属性，否则圆角显示不出来。

fragment_dialog_bg

去掉背景蒙版

需要在 style 中增加 android:backgroundDimEnabled 属性

设置蒙版透明度

在 style 中增加 android:backgroundDimAmount 属性，属性值范围 0 - 1 .

• 0 : 完全透明
• 1：完全不透明

点击 dialog 外部区域，dialog 不消失

重写 onCreateDialog 方法，设置 setCanceledOnTouchOutside 值为 false

public class MyDialogFragment extends BottomSheetDialogFragment {@Overridepublic void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setStyle(STYLE_NORMAL, R.style.MyBottomSheetDialog);}@Overridepublic Dialog onCreateDialog(Bundle savedInstanceState) {Dialog dialog =  super.onCreateDialog(savedInstanceState);dialog.setCanceledOnTouchOutside(false);return dialog;}@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {View view = inflater.inflate(R.layout.bottom_dialog_fragment_layout, container, false);return view;}
}

禁止向下拖动

bottomSheetBehavior.setHideable(false);

具体使用方法：

   @Overridepublic Dialog onCreateDialog(Bundle savedInstanceState) {Dialog dialog = super.onCreateDialog(savedInstanceState);if (dialog instanceof BottomSheetDialog) {BottomSheetDialog bottomSheetDialog = (BottomSheetDialog) dialog;bottomSheetDialog.setOnShowListener(dialogInterface -> {FrameLayout bottomSheet = bottomSheetDialog.findViewById(android.support.design.R.id.design_bottom_sheet);BottomSheetBehavior bottomSheetBehavior = BottomSheetBehavior.from(bottomSheet);bottomSheetBehavior.setHideable(false);});}return dialog;}

设置弹框固定高度

bottomSheetBehavior.setPeekHeight(1200);

使用：

@Overridepublic Dialog onCreateDialog(Bundle savedInstanceState) {Dialog dialog = super.onCreateDialog(savedInstanceState);if (dialog instanceof BottomSheetDialog) {BottomSheetDialog bottomSheetDialog = (BottomSheetDialog) dialog;bottomSheetDialog.setOnShowListener(dialogInterface -> {FrameLayout bottomSheet = bottomSheetDialog.findViewById(android.support.design.R.id.design_bottom_sheet);BottomSheetBehavior bottomSheetBehavior = BottomSheetBehavior.from(bottomSheet);bottomSheetBehavior.setPeekHeight(1200);});}return dialog;}@Nullab

内容铺满全屏

当内容特别多，比如有 recyclerView 时，我们希望 dialog 展开的高度是全屏的。

//默认展开
bottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);

使用

 @Overridepublic Dialog onCreateDialog(Bundle savedInstanceState) {Dialog dialog = super.onCreateDialog(savedInstanceState);if (dialog instanceof BottomSheetDialog) {BottomSheetDialog bottomSheetDialog = (BottomSheetDialog) dialog;bottomSheetDialog.setOnShowListener(dialogInterface -> {FrameLayout bottomSheet = bottomSheetDialog.findViewById(android.support.design.R.id.design_bottom_sheet);BottomSheetBehavior bottomSheetBehavior = BottomSheetBehavior.from(bottomSheet);//默认展开bottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);});}return dialog;}

监听展开收起

bottomSheetBehavior.setBottomSheetCallback()

使用

public class MyDialogFragment extends BottomSheetDialogFragment {@Overridepublic void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setStyle(STYLE_NORMAL, R.style.MyBottomSheetDialog);}@Overridepublic Dialog onCreateDialog(Bundle savedInstanceState) {Dialog dialog = super.onCreateDialog(savedInstanceState);if (dialog instanceof BottomSheetDialog) {BottomSheetDialog bottomSheetDialog = (BottomSheetDialog) dialog;bottomSheetDialog.setOnShowListener(dialogInterface -> {FrameLayout bottomSheet = bottomSheetDialog.findViewById(android.support.design.R.id.design_bottom_sheet);BottomSheetBehavior bottomSheetBehavior = BottomSheetBehavior.from(bottomSheet);//默认展开bottomSheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {@Overridepublic void onStateChanged(@NonNull View view, int newState) {switch (newState) {case BottomSheetBehavior.STATE_EXPANDED:break;case BottomSheetBehavior.STATE_COLLAPSED:break;case BottomSheetBehavior.STATE_DRAGGING:break;case BottomSheetBehavior.STATE_SETTLING:break;case BottomSheetBehavior.STATE_HIDDEN:break;}}@Overridepublic void onSlide(@NonNull View view, float v) {}});});}return dialog;}@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {View view = inflater.inflate(R.layout.bottom_dialog_fragment_layout, container, false);return view;}
}

底部常驻View

在 BottomSheetDialogFragment 实现底部常驻布局是比较难的，好在有些人通过巧妙的方式实现了。

https://github.com/dorianpavetic/StickyBottomSheet

Android: Sticky view at the bottom of bottom sheet dialog fragment