首先再values/themes 或者values/style在文件下编写按钮属性

buttonBarPositiveButtonStyle对应着确认按钮
buttonBarNegativeButtonStyle对应着取消按钮

<style name="AlertDialogTheme">
    <item name="buttonBarPositiveButtonStyle">@style/Alert.Button.Positive</item>
    <item name="buttonBarNegativeButtonStyle">@style/Alert.Button.Negative</item>
</style>

<style name="Alert.Button.Positive" parent="Widget.MaterialComponents.Button.TextButton">
    <item name="backgroundTint">@color/colorPrimary</item>
    <item name="rippleColor">@color/colorAccent</item>
    <item name="android:textColor">@android:color/white</item>
    <item name="android:textSize">14sp</item>
    <item name="android:textAllCaps">false</item>
    <item name="android:layout_marginStart">3dp</item>
</style>

<style name="Alert.Button.Negative" parent="Widget.MaterialComponents.Button.TextButton">
    <item name="backgroundTint">@color/colorPrimary</item>
    <item name="rippleColor">@color/colorAccent</item>
    <item name="android:textColor">@android:color/white</item>
    <item name="android:textSize">14sp</item>
</style>

为Dialog设置风格 new MaterialAlertDialogBuilder(getContext(), R.style.AlertDialogTheme)

AlertDialog.Builder alertDialogBuilder = new MaterialAlertDialogBuilder(getContext(), R.style.AlertDialogTheme)
        .setTitle("添加设备")
        .setPositiveButton(
                "确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                            }
                        });

                    }
                })
        .setNegativeButton("取消", null);
alertDialogBuilder.show();

MaterialAlertDialogBuilder 修改按钮属性

效果图