Android开发：如何将Bottom Sheet高度设置为match_parent？

要让Modal Bottom Sheet的高度扩展至全屏（等同于空Activity的高度），可以通过修改BottomSheetDialogFragment的代码来实现，以下是两种可行方案：

方案一：通过BottomSheetBehavior强制全屏 #

重写BottomSheetDialogFragment的onStart()方法，获取弹窗的Behavior并调整参数，强制弹窗完全展开：

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;

import androidx.annotation.Nullable;

import com.google.android.material.bottomsheet.BottomSheetBehavior;
import com.google.android.material.bottomsheet.BottomSheetDialog;
import com.google.android.material.bottomsheet.BottomSheetDialogFragment;

public class BottomSheetDialog extends BottomSheetDialogFragment {

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable
    ViewGroup container, @Nullable Bundle savedInstanceState)
    {
        View v = inflater.inflate(R.layout.buttom_sheet_layout,
                container, false);
        return v;
    }

    @Override
    public void onStart() {
        super.onStart();
        BottomSheetDialog dialog = (BottomSheetDialog) getDialog();
        if (dialog != null) {
            View bottomSheet = dialog.findViewById(com.google.android.material.R.id.design_bottom_sheet);
            if (bottomSheet != null) {
                BottomSheetBehavior<View> behavior = BottomSheetBehavior.from(bottomSheet);
                // 设置弹窗为完全展开状态
                behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
                // 获取屏幕高度，设置弹窗高度为全屏
                WindowManager windowManager = getActivity().getWindowManager();
                int screenHeight = windowManager.getDefaultDisplay().getHeight();
                behavior.setPeekHeight(screenHeight);
                // 强制布局参数为match_parent
                bottomSheet.setLayoutParams(new ViewGroup.LayoutParams(
                        ViewGroup.LayoutParams.MATCH_PARENT,
                        screenHeight
                ));
            }
        }
    }
}

方案二：通过对话框监听修改布局参数 #

在onCreateDialog()方法中监听弹窗显示事件，直接修改底部布局的参数为全屏：

import android.app.Dialog;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import com.google.android.material.bottomsheet.BottomSheetDialog;
import com.google.android.material.bottomsheet.BottomSheetDialogFragment;

public class BottomSheetDialog extends BottomSheetDialogFragment {

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.buttom_sheet_layout, container, false);
    }

    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
        BottomSheetDialog dialog = (BottomSheetDialog) super.onCreateDialog(savedInstanceState);
        dialog.setOnShowListener(dialogInterface -> {
            BottomSheetDialog bottomSheetDialog = (BottomSheetDialog) dialogInterface;
            View bottomSheet = bottomSheetDialog.findViewById(com.google.android.material.R.id.design_bottom_sheet);
            if (bottomSheet != null) {
                // 强制布局宽高为match_parent
                bottomSheet.setLayoutParams(new ViewGroup.LayoutParams(
                        ViewGroup.LayoutParams.MATCH_PARENT,
                        ViewGroup.LayoutParams.MATCH_PARENT
                ));
            }
        });
        return dialog;
    }
}

额外注意 #

确保你的buttom_sheet_layout.xml根布局高度设置为match_parent，避免布局自身限制高度：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp">

    <!-- 弹窗内部内容 -->

</LinearLayout>

内容的提问来源于stack exchange，提问作者user18148338